Boiler FaultFinder Manual v2 Subscribers(2)

Boiler FaultFinder Manual v2

The professional heating engineer’s complete "Boiler Fault F ault Finder" for boiler and central heating fault finding.

“The boiler SOS "Boiler Fault Finder" results from years of experience as a professional service and repair engineer , demonstrating technical expertise within the industry. The aim of its design is simple; to aid other competent gas operatives within the field, accurately and safely, allowing you to build a base on which to develop your own skills, at your own pace. This technical, yet easy to follow "Boiler Fault Finder" is an invaluable key component within your everyday tool kit.” Copyright (c) 2014 Book name: BOILERFAULTFINDER (v2) Published 1st January 2014 Author: Ty Harnett Web: http://www.boilerfaultfinder.com ALL RIGHTS RESERVED. This book contains material protected under Copyright Laws. Any unauthorized reprint or use of this material is prohibited. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system without express written permission from the author.

(c) 2014 BoilerFaultFinder

2


Notice to purchasers: All individuals in the participation and contribution to this particular "Boiler Fault Finder" will not accept whatsoever, any death, injury, loss or damage, due to error, negligence or however resulted, from the use of this "Boiler Fault Finder". This "Boiler Fault Finder" is solely intended by way of a guide only and is paramount, for all users to exercise exer cise skill and above all, safe judgement at all times when making use of it. By using this "Boiler Fault Finder", each and every ever y user by doing so, agrees to accept full responsibility for their own actions and therefore the refore agrees to indemnify and hold harmless all participants and contributors of this particular "Boiler Fault Finder", from any and all liabilities arising out of or in connection with such use. Any and all such liability is disclaimed.

All purchasers must be Gas Safe Registered to work on boilers and be competent to undertake all other work activities - This is a legal requirement. (For Website).. Manufacturers reserve the right to update and improve their manuals as and when they see fit to do so, without any prior notice. Manuals are correct and up to date at time of print, however, all end users of this particular "Boiler Fault Finder" must mu st use their own judgement to check with the manufacturer if there is any doubt when using the manuals for up to date guidance guidance purposes. All manuals contained within this "Boiler Fault Finder" are original copies in electronic format and the copyright of them remains at all times with the respective manufacturer. No copyrights have been violated whatsoever in the making of this particular "Boiler Fault Finder".

This is a condition of use of this particular "Boiler Fault Finder".


3


Contents System Component Testing ................................................................ .................................................................................9 .................9 Pumps ................................................................ ..............................................................................................................9 ..............................................9 Reasons a pump will fail to start:.................................................................9 Burnt out motor windings ...........................................................................9 Rotor shaft seized s eized ......................................................... ......................................................................................10 .............................10 Worn out bearings ......................................................... .....................................................................................10 ............................10 Fans ...............................................................................................................11 Reasons a fan will fail to start: ................................................................ ...................................................................11 ...11 Burnt Out Motor Windings ......................................................... ........................................................................11 ...............11 Worn Out Bearings ....................................................................................11 Air Rotor Jammed ................................................................ ......................................................................................11 ......................11 Fan Speed Control Resistor........................................................................12 Reasons a resistor will wil l fail to start: ............................................................12 To test a fan speed resistor: ......................................................................12 Temperature Sensors / Thermistors ......................................................... ..............................................................13 .....13 Reasons to affect a thermistor: .................................................................13 Two types of thermistor: ............................................................. ...........................................................................13 ..............13 Typical Sequence: ................................................................ ......................................................................................13 ......................13 To Test a Thermistor: Thermis tor:........................................................... .................................................................................13 ......................13 Graphs Representing resistance versus v ersus temperature ................................15 Potentiometers .............................................................................................16 To Test a Potentiometer (three pin connector): ........................................17 To Test a Potentiometer (two pin connector): ..........................................18 Alternative test (where manufacturers resistance readings are known example): ................................................................ ...................................................................................................18 ...................................18 Thermostats (liquid expansion / vapour pressure type/ Over heat h eat cut out) .21


4

Boiler FaultFinder Manual v2 Liquid expansion / vapour pressure...........................................................21 To test a Liquid expansion expansi on / vapour pressure press ure type thermostat: ................21 To test a Liquid expansion expansi on / vapour pressure press ure type thermostat .................22 To test an over heat cut out thermostat (when not no t at trip point): ............23 To test an over heat cut out thermostat (when at trip point reaching 90-98 degrees C): ................................................................ .................................................................................................23 .................................23 Air pressure switches (operating @ approx. 0.5 – 4 m/bar m /bar pressures) ..........25 To test a two wire air pressure switch (no demand): ................................26 To test a two wire air pressure switch (on a demand):..............................27 To test a three wire air pressure switch swi tch (no demand): ..............................27 To test a three wire air pressure switch (on a demand): ...........................28 Domestic hot water flow switches ................................................................30 To test a domestic hot water flow switch swi tch (on a demand): ........................30 Primary water flow switches .....................................................................30 To test a primary water wa ter flow switch (on a demand): .................................31 Domestic hot water and primary pri mary micro switches swi tches ..........................................32 To test a domestic hot ho t water and primary micro mic ro switch (on a demand): d emand): ..32 Low water pressure switches ........................................................................33 To test a low water pressure switch (pressurised state): ..........................34 To test a low water pressure switch (unpressurised (unpressu rised state): ......................34 Solenoids .......................................................................................................35 To test a solenoid: .....................................................................................36 Modureg adjustments (early production boilers) ..........................................37 Modureg adjustments (later production models) .........................................38 Actuators (motorised valves).........................................................................39 To test an actuator: (proving the room stat, cylinder stat and programmer is working ok) ............................................................................................40 Synchronous motors (within zone valves) .....................................................41


5

Boiler FaultFinder Manual v2 To test a synchronous motor: ................................................................ ....................................................................41 ....41 Y Plan (3 port mid-position valve)..................................................................42 S plan (HW zone zo ne valve and HTG zone valve) ..................................................44 Sequence of operation: .............................................................................45 A typical Y plan schematic: ........................................................................46 A typical S plan schematic: ........................................................................47 Motorised valve heads (diverter valves)........................................................49 To test a motorised mo torised valve head he ad lead: ........................................................ .........................................................49 .49 To test motorised valve head: ...................................................................50 Diverter valves ................................................................ ...............................................................................................51 ...............................51 To test a diverter valve valv e .......................................................... ..............................................................................51 ....................51 Room thermostats ........................................................... .........................................................................................53 ..............................53 To test a room thermostat ........................................................................53 Cylinder thermostats ........................................................... .....................................................................................55 ..........................55 Spark electrode(s)..........................................................................................57 To test spark electrode(s) ................................................................ ..........................................................................57 ..........57 Sequence of boiler operation: ope ration: ................................................................ ...........................................................................59 ...........59 Central Heating Mode ...............................................................................59 Hot Water Mode .......................................................................................59 Electrical safety checks ........................................................... ......................................................................................61 ...........................61 Mains voltage test (dead ( dead test) ......................................................... .......................................................................61 ..............61 Earth continuity test (dead test) ................................................................ ....................................................................62 ....62 Short circuit (dead test) ........................................................... .................................................................................65 ......................65 Components to check (in this sequence): ..................................................65 Resistance to earth (dead test)......................................................................67 Mains voltage and polarity tests ...................................................................69 General fault finding ............................................................. ..........................................................................................74 .............................74


6

Boiler FaultFinder Manual v2 Domestic hot water w ater fault finding ................................................................ ...................................................................79 ...79 No domestic hot water ................................................................ ..............................................................................79 ..............79 Domestic hot water too hot ......................................................................79 Domestic hot water not hot enough .........................................................80 Central heating fault finding ............................................................. ..........................................................................81 .............81 No Central Heating ....................................................................................81 Central Heating Too Hot ............................................................................81 Central Heating Not Hot Enough ...............................................................82 Top tips........................................................... ..............................................................................................................83 ...................................................83 Safe use of multimeter functions ......................................................................87 Boiler servicing procedure – the professional’s approach .................................89 Maximising condensing operation ....................................................................92 Example: ................................................................ ....................................................................................................94 ....................................94 Programmer and time switch compatibility guide ............................................96 24 hour programmer compatibility guide .....................................................98 5/2 day programmer programm er compatibility compatibili ty guide ....................................................100 7 day programmer compatibility guide .......................................................102 24 hour time switch compatibility guide .....................................................104 5/2 day time switch compatibility guide .....................................................106 7 day time switch compatibility comp atibility guide .........................................................107 Programmer terminal comparisons ............................................................ .............................................................109 .109 Time switch terminal termi nal comparisons ......................................................... ..........................................................112 .112 Asbestos – the hidden dangers! ......................................................................114 Boilers known to contain con tain asbestos ..............................................................1 ..............................................................115 15 st

Notching and Drilling requirements in joists when 1 fixing ...........................125 Requirements for notching notchi ng traditional joists ...............................................126 Requirements for drilling drilli ng holes through traditional joists joi sts ...........................127


7

Boiler FaultFinder Manual v2 Engineering joists ........................................................................................128 Notching traditional joists .......................................................................129 Drilling holes through traditional joists ...................................................129 A Typical Service & Repair Engineer’s Toolkit ..................................................130 Hand tools ...................................................................................................130 Consumables ...............................................................................................131 Up to Date Pocket Reference Guides ..........................................................132 Forms / Labels .............................................................................................132


8


System Component Testing Pumps Reasons a pump will fail to start: No 240V supplying (L) & (N) terminals Faulty capacitor Rotor shaft seized or debris preventing impeller rotation rota tion Burnt out motor windings Worn out bearings • • • • •

240 V LIVE TEST Always check across red or brown and black or blue with multimeter mu ltimeter set on correct voltage scale. (If no voltage is evident e vident at pump terminals, check for demand via programmer/timer, room thermostat or cylinder thermostat).

Burnt out motor windings • • •

Electrically isolate boiler / system controls Remove E N L wires from pump terminals Set multimeter on ohms scale for resistance readings, across L N at pump terminals:

less than 100 ohms = replace No resistance/infinity = replace Approx. 120 ohms – 250 ohms = ok Note: A good indication when 3 amp fuses and or “quick - blow” glass type fuses repeatedly fail is when the motor windings have burnt out. When 240V is present at the pump terminals and the rotor shaft is free fr ee moving (anti-clockwise), but still refusing to mechanically spin, then you know the motor windings have burnt out. (This is due to the rotor shaft seizing at some point and causing causing the pump motor windings to overheat).


9


Rotor shaft seized • • •

Electrically isolate boiler Remove vent plug on pump head Manually, turn rotor shaft (ant-clockwise) several times (Resistance being felt and or not spinning or spinning but with resistance donates a new pump head).

Worn out bearings • •

Electrically isolate boiler / system controls Remove vent plug from pump head:

If water severely escapes, bearings are worn out (new pump needed) If a small amount escapes, this is to be expected and is quite normal.


10


Fans Reasons a fan will fail to start: • • • • • •

No 240V supplying (L) & (N) terminals Burnt out motor windings Worn out bearings Air rotor jammed (on fan casing) impeller heavy with foreign matter accumulation Faulty fan speed control resistor (if fitted)

Burnt Out Motor Windings • • •

• • •

Electrically isolate boiler / system controls Remove E N L wires from fan terminals Set multimeter on ohms scale for resistance readings, across L N at fan terminals: less than 20 ohms = replace No resistance/infinity = replace (30 ohms – 100 + ohms) = ok

240 V LIVE TEST Set multimeter to correct voltage scale and check at fan motor terminal leads Should 240V be present at leads but the fan impeller imp eller runs smoothly and freely (without resistance) then the motor windings are burnt out

Worn Out Bearings • • •

•

Electrically isolate boiler / system controls Remove fan assembly Carry out a visual assessment on the balance and smooth running of the impellor. Should the fan impellor be out of alignment alignm ent and or noisy, replace with new fan assembly.

Air Rotor Jammed Jammed Due to the high temperatures and mechanical wearing, the air rotor can be subject to going out of alignment, catching on the fan casing and jamming.


11

Boiler FaultFinder Manual v2 Re alignment may be possible, however, it may also be loose and beyond repair.

Fan Speed Control Resistor The fan speed control resistor is able to withstand wi thstand larger currents so as to generate heat. The resistors are enclosed within a metal casing casin g with a heat sink connected to it, which then connects to the boiler chassis to dissipate the heat quickly. Because of the heat sink absorbing the high temperature rise, it prevents damage to the enclosed resistor.

Reasons a resistor will fail to start: • • •

Burnt out Melted connections Loose connections

To test a fan speed resistor: • • •

Electrically isolate boiler / system controls Remove leads from resistor Set multimeter on ohms scale for resistance readings, across resistor connections:

Test No resistance/infinity Resistance reading (may vary)

Outcome faulty ok

A bad connection will increase resistance resis tance and as a result may drop the fan speed performance, which in turn, may affect the air pressure pressu re switch resulting in no combustion.


12


Temperature Sensors / Thermistors Reasons to affect a thermistor: • • • •

Scale / magnetite deposits affecting heat transfer / sensitivity System water ingress (causing open circuit / infinity) Loss in manufacturers calibration Damaged terminals / connections

Two types of thermistor: NTC (Negative temperature co-efficient) PTC (Positive temperature co-efficient)

NTC Thermistor Shows a decrease of electrical resistance when the system water wa ter increases in temperature and shows an increase of electrical resis tance when the system water decreases in temperature. PTC Thermistor Shows an increase of electrical resistance when the system s ystem water increases in temperature and shows a decrease of electrical resistance resis tance when the system water decreases in temperature.

Typical Sequence: As the system water increases in temperature, the resistance of the NTC thermistor, decreases, and the potentiometer at the p.c.b then varies the voltage to the modureg on the gas valve, which in turn, modulates the burner accordingly, to match the demand for the heat load.

To Test a Thermistor: • •

•

•

Electrically isolate boiler / system controls Ascertain system water temperature (near to thermistor) by using a thermal laser or clamp on thermal sensor Remove thermistor wires (at the p.c.b end) to prevent stray resistances from the p.c.b itself Set multimeter on ohms scale for resistance readings


13

Boiler FaultFinder Manual v2 Note: (PTC thermistors only: the black lead from the multimeter must go on the metal casing of the sensor and the red lead from the multimeter must go on the terminal of the sensor. Resistance readings must be cross referenced ref erenced to that of the manufacturer specification, to prove correct manufacturer calibration.

Test Closed circuit of less than 1 ohm No resistance/infinity

Outcome faulty faulty

An example of NTC resistance values: Temperature (degrees C) 0 10 20 25 30 40 50 60 70 80 90 100 110

Resistance (ohms) 35400 22500 14700 12000 9835 6712 4672 3311 2388 1749 1300 980 749


14


Graphs Representing resistance versus temperature NTC thermistor

PTC thermistor


15


Potentiometers Potentiometers (potential dividers) are a variable resistor which, depending on the function it is used for, can be adjusted either by the end user (electronic thermostat knob on front fascia numbered 1-6 providing the set point, which could be between 54 degrees C and 82 degrees C), or by the engineer for onsite technical adjustments (within the inner face of the printed circuit board to adjust fan speeds, gas pressures / range rating, maximum operational temperatures, service mode and time delay periods). Potentiometers work by introducing a voltage across a fixed top and bottom connection on a metallic plate or coil of wire. A third connection, called the wiper connection, is positioned between the top and bottom connections and attached to a rotating shaft. The wiper rotates along the length of the plate or coil. If the wiper is positioned close to the top connection, almost all of the supply voltage is available at this connection. As the rotating shaft is turned, the voltage supplied to the wiper is moved from the top connection. A small measured direct current (DC) is passed from the printed circuit board into the potentiometers top connection. This current travels along the metallic plate or wire coil and returns to the printed circuit board via the bottom connection. The wiper connection voltage is governed by its position in relation to the top and bottom connection. The values of the top and wiper connections are then compared by the printed circuit board. The difference between these two voltages is then interpreted by the printed circuit board and used to determine the required temperature. When a potentiometer is used to control the primary or secondary water temperatures, it will dictate the parameters in which the boiler will work. As the temperature being measured approaches the potentiometers s et point, the gas rate / gas pressure will adjust to maintain the correct temperature. The potentiometer will normally work in conjunction with a thermistor, p.c.b and gas valve modureg or fan speed control.


16

Boiler FaultFinder Manual v2 When potentiometers fail, the information it sends to the printed circuit board may indicate no demand for heat or gives a demand for the boiler to be raised to maximum temperature. Rotating the potentiometers control dial will not change the information to the printed circuit board, symptoms such as no heating, boiler shutting down at low temperatures or overheating are signs of failure.

To Test a Potentiometer (three pin connector) c onnector):: Note: Manufacturers resistance readings will vary and must be checked for correct operation • •

• • •

Electrically isolate boiler / system controls Remove potentiometer wires (at the p.c.b end) to prevent stray resistances from the p.c.b itself (Some potentiometers are built into the p.c.b and are sealed units, so not possible) poss ible) Set multimeter on ohms scale for resistance readings Turn potentiometer to fully OFF position Connect multimeter leads to bottom connection and to wiper (middle) connection on three pin connector of potentiometer 1 ohm = ok

Test Switch to ON position but no more further 1 ohm Slowly turn potentiometer to FULL ON position where the resistance reading decreases proportionally to 0 ohms No variation when rotated •

Outcome ok ok

faulty

Connect multimeter leads to top connection and to wiper wi per (middle) connection on three pin connector of potentiometer

Test Turn potentiometer to fully OFF position 0 ohms Slowly turn potentiometer to FULL ON position where the resistance reading

Outcome ok ok


17


Test increases proportionally to 1 ohm Off position again should read 0 ohms

Outcome ok

To Test a Potentiometer (two pin connector): • •

• • •

Electrically isolate boiler / system controls Remove potentiometer wires (at the p.c.b end) to prevent prev ent stray resistances from the p.c.b itself (Some potentiometers are built into the p.c.b and are sealed units, units , so not possible) Set multimeter on continuity buzzer mode Turn potentiometer to fully OFF position Connect both multimeter leads to both connections on potentiometer

Test Turn potentiometer to ON position continuity No continuity

Outcome ok faulty

Alternative test (where manufacturers resistance readings are known example): Potentiometer off (fully ant-clockwise) Connections to test resistance (K Ohms) Top / bottom 9.6 Top / wiper 0 Bottom / wiper 9.6 Potentiometer on (fully clockwise) Connections to test Top / bottom Top / wiper Bottom / wiper

resistance (K Ohms) 9.6 9.6 0


18

Boiler FaultFinder Manual v2 If the readings are comparable with the manufacturers readings, the potentiometer can be assumed as working. A non-functioning potentiometer will normally give no variation between connections conn ections when the shaft is rotated.


19



20


Thermostats (liquid expansion / vapour pressure type/ Over heat cut out) Liquid expansion / vapour pressure Reasons to affect a liquid / vapour expansion type thermostat: • • •

Contact points worn out, burnt out or pitted Loss in manufacturers calibration Phial incorrectly located into pocket

The unit consists of a remote phial (located within or very near to heat exchanger) and a capillary tube that joins it to the bellows chamber. Within the phial is a volatile fluid having a rapid expansion rate. As the phial heats up, the fluid expands, in some cases changing to a vapour, and passes through the small capillary tube to fill the bellows. The bellows in turn, increases in size to take up this expansion and in so doing, breaks the electrical circuit and extinguishes the pilot and / or mai n burner. On cooling, the volatile fluid contracts and is forced back by the pressure of a spring acting on the bellows, through the capillary tube to the phial and remaking the electrical circuit once more to relight the pilot and / or main burner.

To test a Liquid expansion / vapour pressure type thermostat: Liquid expansion / vapour pressure type thermostat – (thermostat calling) • • •

Electrically isolate boiler / system controls Remove E N L wires from thermostat terminals Set multimeter on ohms scale for resistance readings, across L N at thermostat terminals:


21


Test Closed circuit of less than 1 ohm No resistance/infinity Continuity

Outcome ok faulty ok

Liquid expansion / vapour pressure type thermostat – (thermostat satisfied) • • •

Electrically isolate boiler / system controls Remove E N L wires from thermostat terminals Set multimeter on ohms scale for resistance readings, across L N at thermostat terminals:

Test Closed circuit of less than 1 ohm No resistance/infinity No continuity

Outcome faulty ok ok

To test a Liquid expansion / vapour pressure type thermostat

240 V LIVE TEST • •

Boiler thermostat on maximum setting (thermostat calling) Set multimeter to correct voltage scale and check for 240V AC between NC and N (neutral)

Zero voltage = faulty • •

Turn boiler thermostat to O min setting (satisfied) (s atisfied) Set multimeter to correct voltage scale and check for 0V AC between NC and N (neutral)

240V AC = faulty The control thermostat may rest in a Normally Normall y Open (NO) position of this type. On some control thermostats, the manufacturer may need to be consulted in order to identify the relevant terminal connections for correct operation.


22


Over heat cut out thermostat (Set @ approx. 90 – 98 degrees C)

Reasons to activate an over heat cut out thermostat: • • • • • • •

Scale / magnetite deposits causing excessive heat build up Loss of system water Loss in manufacturers calibration Faulty pump or pump speed too low Too much air within system water Faulty expansion vessel (loss in air charge or split diaphragm) Faulty gas pressures / solenoid stuck in on position

These thermally activated control devices may interrupt the electricity supply to a gas solenoid valve extinguishing the pilot and/or main burner, signalled by the printed circuit board. The overheat cut out thermostat must be manually reset to prevent further boiler cycling whilst a fault may be present (overheat lockout).

To test an over heat cut out thermostat (when not at trip point): • • •

Electrically isolate boiler / system controls Remove wires from thermostat terminals Set multimeter on ohms scale for resistance readings, across thermostat terminals:

Test Continuity across terminals No continuity across terminals

Outcome ok faulty

To test an over heat cut out thermostat (when at trip point reaching 90-98 degrees C): • •

Electrically isolate boiler /system controls Remove wires from thermostat terminals


23

Boiler FaultFinder Manual v2 •

Set multimeter on ohms scale for resistance readings, across thermostat terminals:

Test Continuity across terminals No continuity across terminals

Outcome ok faulty


24


Air pressure switches (operating @ approx. 0.5 – 4 m/bar pressures) Reasons an air pressure switch will fail to start: • • • • • • • • • • • • •

Loose electrical connections Kinked or split rubber hoses / loose hose connections Condensation within rubber hoses Blocked venturi / melted venturi within fan assembly Reversed rubber hose connections Internal rubber diaphragm perished / damaged Poorly installed flue seals Flue way blocked Faulty fan assembly (slow running) runn ing) Incorrect flue lengths Incorrect or no restrictor rings in flue assembly Inadequately sealed combustion chamber (poor casing seals) Faulty electrical micro switch assembly

The pressure differential created by the fan is transmitted via the pressure hoses and creates a difference in pressure on top and bottom of the diaphragm, this in turn, pushes the diaphragm and an attached pin and lever. When the diaphragm has fully reached its proved air flow position, the pin and lever operate a micro switch, sending a signal to the printed circuit board to commence ignition sequence (by either a 2 or 3 wire configuration). When the fan has stopped, a force (usually a spring or gravity) returns the diaphragm to its rest/no air flow position.

2 wire configuration: C – Common NC – Normally closed 3 Wire configurations:


25

Boiler FaultFinder Manual v2 C – Common NC – Normally closed NO – Normally open

C – Common: Printed circuit board signal (voltage) (vol tage) to the air pressure switch Normally open (NO): Air pressure switch returns signal s ignal (voltage) to printed circuit board, once the fan is operating and a proved air flow is established. Normally Closed (NC): Rest mode / no air flow and the return from the NC terminal must mus t be proved at the printed circuit board before next ignition sequence takes place. When the fan operates effectively and air is proved at the air pressure switch, the micro switch moves to the proved air flow position NO terminal. Some air pressure switches are marked with +ve or 1 and –ve or 2. (1 being positive and 2 being negative). Some air pressure switches are marked with L and H. (L being negative and H being positive).

To test a two wire air pressure switch (no demand): • • •

•

Electrically isolate boiler / system controls Disconnect both wires from the switch terminals Ensure both wires are resting safely and not touching to uching any other component or earth - a well insulated ins ulated heat mat is good for this Set multimeter on ohms scale for resistance readings, across switch terminals (black test lead to C and red test lead to NC)

Open circuit (infinity) across both terminals = ok (switch ( switch in rest / no air flow position)


26


To test a two wire air pressure switch (on a demand):

•

• •

•

240 V LIVE TEST Ensure both wires are still resting safely s afely and not touching any other component or earth Restore power and create a demand for heat Set multimeter on ohms scale for resistance readings, across switch terminals (black test lead to C and red test lead to NC) N C) With fan running (at high speed) check continuity/resistance readings across both switch terminals.

Note: Some appliances will give you very little time to check a proved air flow – ensure the fan is at high speed for this check.

Test Continuity Closed circuit of less than 1 ohm

Outcome ok (switch in proved air flow position) ok (switch in proved air flow position)

Should an open circuit (infinity) reading be present, it does not prove a fault f ault with the switch itself, but could be fan, venturi, blockages, hose problems etc needs - further investigation. Electrically isolate boiler - Replace both wires back onto their respec tive terminals - Restore power once more

To test a three wire air pressure switch (no demand): • •

•

•

•

•

Electrically isolate boiler / system controls Disconnect all three wires from the switch terminals (note positions and colours respectively) Ensure all three wires are resting safely and not touching any other component or earth (a well insulated heat mat is good for this) Join safely both the C and NC wires together (two ( two spade connectors joined together are good for this) Set multimeter on ohms scale for resistance readings, across switch terminals (black test lead to C and red test lead to NC) N C) Closed circuit of less than 1 ohm = ok (switch in rest / no air flow position)


27


Continuity = ok (switch in rest / no air flow position.

To test a three wire air pressure switch (on a demand):

•

•

• •

•

240 V LIVE TEST Ensure all wires are still resting safely and not touching any other component or earth With the C and NC wires still touching (simulating rest / no air flow position), the fan should run at its normal high speed Restore power and create a demand for heat Set multimeter on ohms scale for resistance readings, across switch terminals (black test lead to C and red test lead to NO) N O) With fan running (at high speed) check continuity/resistance continui ty/resistance readings across both switch terminals.

Note: Some appliances will give you very little time to check a proved air flow – ensure the fan is at high speed for this check.

Test Continuity Closed circuit of less than 1 ohm

Outcome ok (switch in proved air flow position) ok (switch in proved air flow position)

Should an open circuit (infinity) reading be present, it does not prove a fault f ault with the switch itself, but could be fan, venturi, blockages, hose problems etc (needs further investigation). Electrically isolate boiler replace both wires back onto their respective terminals and restore power once more. Where an air pressure switch is not present, purposely designed thermistors are used to measure the differential temperatures of the flue/air ducts, which are then transmitted to the printed circuit board for correct operation. Some boilers use a low DC voltage, whereas others o thers use a 240 V AC voltage. (Remember - the input will appear as an output, unless a fault is present). Some air pressure switches use a push pu sh (positive) pressure on the diaphragm to make the micro switch, whereas others will use a pull (negative) pressure on the diaphragm to make the micro switch. The operation depends on the position of the return force (spring or gravity) when the fan is at rest.


28

Boiler FaultFinder Manual v2 A continuity check of the the wiring harness at the printed circuit board end will ascertain correct operation of switch and the integrity i ntegrity of wires also, where it is difficult to gain access.


29


Domestic hot water flow switches Reasons a domestic hot water flow switch will fail to operate: • •

• • • •

Switch contact faulty Internal paddle / turbine / wheel not free moving (stiff/seized/reversed water flow) Punctured / perished rubber diaphragm Blocked pressure differential sensing pipes (scale deposits) Damaged / loose wiring harness Seized bearing plate spindle / out of alignment

A demand for domestic hot water will either activate a turbine arrangement, a paddle / wheel arrangement or a rubber diaphragm arrangement, all of which communicating to a micro switch assembly, transmitting t ransmitting a signal to the printed circuit board for correct operation.

To test a domestic hot water flow switch (on a demand): Pressure differential type: Visually assess whether bearing plate spindle is rising through gland nut, activating the micro switch assembly above. (No (N o spindle movement may be due to a perished rubber diaphragm and/or seized seiz ed bearing plate spindle and/or blocked pressure differential sensing pipes. Where pressure differential sensing pipes exist, it may save time to check for any scale deposits present, prior to stripping down the flow switch assembly to assess the spindle and/or diaphragm). Inline paddle/turbine/wheel type: A continuity check of the wiring harness at the printed circuit boa rd end will ascertain correct operation of integral switch and the integrity of wires also.

Primary water flow switches sw itches Reasons a primary water flow switch will fail to start: • •

Punctured / perished rubber diaphragm Seized bearing plate spindle / out of alignment


30

Boiler FaultFinder Manual v2 • •

Damaged / loose wiring harness Switch contact faulty

A demand for central heating will activate the pump and a rubber rubb er diaphragm / spindle arrangement communicates to a micro switch s witch assembly above, transmitting a signal to the printed circuit board for correct operation.

To test a primary water flow switch (on a demand): Pressure differential type: Visually assess whether bearing plate spindle is rising through gland nut, activating the micro switch assembly above. (No spindle movement may be due to a perished rubber diaphragm and/or seized bearing plate spindle).


31


Domestic hot water and primary micro switches Reasons a domestic hot water and primary micro switch will fail to start: • •

Switch contact faulty Damaged / loose wiring harness

To test a domestic hot water and primary micro switch (on a demand): • • •

•

Electrically isolate boiler / system controls Set multimeter to continuity “buzzer” scale A continuity check of the wiring harness at the printed circuit circui t board end will ascertain correct operation of switch and the integrity of wires also. No continuity present will be a complete new assembly ass embly (micro switch with wiring harness).

Test Continuity between C and NC Continuity between C and NO

Outcome ok faulty


32


Low water pressure switches Reasons a low water pressure switch will fail to start: • • • • •

Damaged / loose wiring harness Switch contact faulty Blocked hole (sludge deposits) Calibration of switch faulty Air trapped within switch

The low water pressure switch receives 230V AC from the printed circuit board via the (C) and upon adequate system pressure being applied appli ed (0.5 bar and above typically) the switch will then return 230V AC back to the printed circuit board via the (NO). The switch when new or when there is inadequate system pressure applied, will rest in the (NC) position, pos ition, and only upon there being adequate system pressure again, will it switch over to the (NO) position. Not all boilers incorporate these switches swi tches to detect a low water system pressure, but instead rely just on the high limit li mit thermostat to protect the main heat exchanger. Some switches are only a two wire connection only (there is not a NC connection). On some pressure switches, the manufacturer may need to be consulted in order to identify the relevant terminal connections for fo r correct operation.


33


To test a low water pressure switch (pressurised state): • • •

Electrically isolate boiler / system controls Remove wires from terminals Set multimeter on ohms scale for resistance readings, across pressure switch terminals:

Test Measuring between C and NC - No resistance/infinity Measuring between C and NC – closed circuit of less than 1 ohm

Outcome ok

Test Continuity between C and NO Continuity between C and NC

Outcome ok faulty

faulty

To test a low water pressure switch (unpressurised state): • • •

Electrically isolate boiler Remove wires from terminals Set multimeter on ohms scale for resistance readings, across pressure switch terminals:

Test Measuring between C and NC - closed circuit of less than 1 ohm Measuring between C and NC - No resistance/infinity

Outcome ok

Test Continuity between C and NC Continuity between C and NO

Outcome ok faulty

faulty


34


Solenoids Reasons a solenoid will fail to operate: • • • •

•

Burnt out coil Poor terminal connection Loose mountings Armature sticking (Foreign matter accumulation jamming the armature) Faulty printed circuit board

These electromagnetic devices are utilised to control the on/off/flow of gas through modureg gas valves. These are energised by either AC or DC current (often colour coded to indicate 24V blue and 230V black or red). As voltage is applied to the coil, the armature is drawn into the solenoid valve body, allowing gas to flow through the main gas valve which is proportional to the current applied. The modulation (varying current) increases or decreases gas flow/rate to match the heat load placed on the boiler. The temperature of the thermistor indirectly controls the amount of current the potentiometer sends to the solenoid. Typically, the pilot solenoid and main solenoids are are 230V AC and the modulating solenoid approx. 24V DC, but manufacturer instructions/data must always be checked.


35


To test a solenoid: • • • •

•

•

• •

Electrically isolate boiler / system controls Inspect terminal connections Ascertain correct solenoid voltage (manufacturer instructions) Turn on power supply to boiler

240 V LIVE TEST Set multimeter to correct voltage scale and check at connections (AC or DC) Incorrect reading maybe faulty printed circuit board – needs further investigating Correct voltage but not operating - electrically isolate boiler Set multimeter to Ohms scale and measure coil c oil resistance:

Test No resistance/infinity Less than 1 Ohm Modureg coil resistance 45 +Ohms approx*

Outcome faulty faulty ok

*(This will vary depending on manufacturer and type of solenoid. Some modern two stage safety solenoids may be 165 + ohms)


36


Modureg adjustments (early production boilers) Maximum adjustment: • •

• • • • •

•

Electrically isolate supply Remove the modulator solenoid coil by releasing the spring clip and pull away from the brass spindle Turn the small black minimum rate adjusting screw s crew fully clockwise Loosen the locking nut which secures the spindle spi ndle to the gas valve Turn on power supply to boiler Call for a demand via fully full y opening a hot tap Rotate the brass spindle clockwise to increase increas e the pressure to maximum setting (if needed) Tighten locking nut

Minimum adjustment: • •

• • •

With the burner still running at maximum setting Slowly unscrew the small black minimum rate adjusting screw at the end of the spindle until the correct pressure is attained Electrically isolate supply Refit the modulator solenoid coil with spring clip onto brass spindle Turn on power supply to boiler


37


Modureg adjustments (later production models) On moduregs where the minimum and maximum adjustment nuts are enclosed behind a plastic cover, always check with manufacturer instructions first before making any adjustments. For most boilers, the large nut is for maximum pressure and the small nut is for minimum pressure, however, there are some boilers which are arranged opposite to this (large nut is minimum and small nut is maximum). In order to adjust the maximum pressure, call for a demand via fully opening a hot tap and turn the large nut clockwise to increase whilst at the same time, holding the minimum screw still. In order to adjust minimum pressure, remove one of the wires from the modureg coil terminals (this automatically drops the pressure down to low rate) and turn the small screw clockwise to increase (the large nut will not freely move so no need to hold during this adjustment). On modern gas/air ratio valves, v alves, the manufacturer’s instructions must always be followed when adjusting them. In order to achieve the correct CO / CO2 ratio at time of service or periodic inspection, the appliance must be forced into “service mode” where the gas adjustments are then made via the offset adjuster (minimum rate) and throttle adjuster (maximum (maxim um rate). Note: Whenever a gas valve of this type is replaced r eplaced or adjusted, a calibrated electronic combustion gas analyser MUST be used to ensure correct corr ect operation. Finally, an inlet pressure check at the gas valve, working pressure pres sure at the metre and a tightness test should be carried out on completion of commissioning.


38


Actuators (motorised valves) Reasons an actuator will fail to operate: • • • • • •

Burnt out synchronous motor windings Valves spindle seized /sludge contamination Auxiliary switch (end switch) burnt out Gearing worn out Loose mountings Poor terminal connection

These devices are energised or de energised to control the on/off of pump and boiler (calling from the cylinder thermostat or room thermostat). Two port valves are either in the open or closed position via the internal ball (shoe or paddle). 3 port diverter valves (hot water priority valves) control one circuit only; not both, (hot water or heating). Once the hot water cylinder thermostat is satisfied, the central heating port will open. 3 port mid-position valves control both circuits at the same time or independently from one another, (depending on demands). When these valves are de energised “at rest” it defaults in hot water position (port B for hot water will always be open). This is why “blocker valves” (an additional two port zone valve) must be installed after port B on a mid position valve when installed on an unvented hot water cylinder system, to prevent the stored s tored water from overheating / over pressurising. Should the synchronous motor burn out, it is possible to replace the motor, however, if the end switch fails, a complete actuator a ctuator must be replaced. The manual override lever should only be used for draining and refilling purposes and not as a solution to heat the hot water and/or central heating, in case of the actuator failing.


39

Boiler FaultFinder Manual v2 Should the manual override lever fail to move or too much resistance is felt, the valve and actuator should be replaced and investigate the condition of system water (magnetite maybe present).

Warning: Some very old actuator heads require the system to be drained first, before separating from the brass valve body. Experience has shown that actuator covers not having a raised pip (reversed dimple) on top of the cover, are the type which will leak if separated from the brass body, prior to draining.

To test an actuator: (proving the room stat, cylinder stat and programmer is working ok) Manually override lever to open position and call for a demand via room or cylinder thermostat (with timer or programmer calling). callin g). Should boiler / pump not respond, the auxiliary switch may be faulty (new actuator needed) Manually override lever to open position and call for a demand via room or cylinder thermostat (with timer or programmer calling). callin g). Should boiler / pump respond, the syncron motor will be faulty (new motor needed)


40


Synchronous motors (within zone valves) These small motors are powered by 240V AC to rotate a spring loaded gearing arrangement, which in turn, rotates the spindle to open op en / close the valve. The motor windings can overheat and break, which is a common fault when motorised valves fail to operate.

To test a synchronous motor: • •

•

Electrically isolate boiler / system controls Cut both factory fitted wires exiting the syncron motor (but near to the already factory fitted crimp connections). Set multimeter on ohms scale and measure resistance r esistance readings through the windings:

Test Approx. 2.4K ohms No resistance / Infinity

Outcome ok (resistance will vary depending on manufacturer) faulty

Purposely designed insulated wire crimps are easily obtained and must be used to reconnect the broken wires safely. When replacing faulty syncron motors, the two factory fitted wires do vary in colour (orange, blue and white), however, this will not matter as long as it fits onto the actuator head, designed for this purpose. purpos e.


41


Y Plan (3 port mid-position valve) Suspect the mid-position valve as being faulty if the valve does not operate after the following checks (in order):

Heating mode: •

• • •

•

•

•

•

•

•

Electrically isolate mains supply and remove fuse - always check a 3 amp fuse is fitted Remove junction box cover Ensure there is no 240V present at L and N terminals termi nals in junction box Disconnect the grey wire from the valve (this connects to HW off on the time controller and may also connect to terminal termin al 2 on cylinder stat which may be the satisfied terminal) Disconnect also, the white wire from the valve (this may m ay connect to terminal 3 on the room stat which may be the th e calling terminal) Connect both the grey and white wires to the permanent live liv e terminal in junction box (this should shoul d force the valve to a HW off but CH on position, once connected to mains supply) Switch on mains supply – valve motor should now move to fully open the heating (port A) Once fully open, it should stay in this position pos ition as long as power is applied to the white and grey wires When (port A) is fully open, the orange wire becomes b ecomes live to start the pump and boiler Always check (port A) outlet has a temperature rise and is progressively getting warmer

Hot water mode: Electrically isolate mains supply and remove fuse fus e - always check a 3 • amp fuse is fitted Once the valve has been de-energised, the HW (port (po rt B) will rest in • open position and close the HTG (port A) Remove the grey and white wires from the permanent p ermanent live connection • (from before) and temporarily make safe (not connected connec ted to terminal block at all or touching one another)


42


•

•

•

Remove cylinder stat wire only from terminal 6 (common) - This should connect to ‘HW ON’ on the time controller Then connect the wire to permanent live (this should force the valve to a HW on but CH off position once connected to mains supply) Switch on fused spur, cylinder stat must be calling for heat – pump and boiler should start Always check (port B) outlet has a temperature rise and is progressively getting warmer

Hot water and heating mode together: Electrically isolate mains supply and remove fuse fus e - always check a 3 • amp fuse is fitted Replace cylinder stat wire back to terminal 6 (common) (common ) • Keep grey wire made safe but connect white wire wi re temporarily back to • permanent live Switch on fused spur, motor should now move to mid-position and • stop Cylinder stat must be calling for heat and both ports (A and B) are now • open, boiler and pump should start Always check (port A and B) outlets have a temperature te mperature rise and are • progressively getting warmer Electrically isolate mains supply, reconnect white and grey wires back • to their respective terminals in the junction box. In some cases, there may not appear to be any numbers on the terminals termin als within the junction box. In these situations, trace back the respective wire from the cylinder stat. If this functional check proves to be correct, the problem is not the motorised valve, but elsewhere in the circuit – possibly cylinder stat or room stat.


43


S plan (HW zone valve and HTG zone valve) Suspect the zone valve as being faulty if the valve v alve does not operate after the following checks: •

• • •

Electrically isolate mains supply and remove fuse - always check che ck a 3 amp fuse is fitted Remove junction box cover Ensure there is no 240V present at L and N terminals term inals in junction box Remove metal cover from motorised valve head

Turn electrical mains supply back on – be aware of 240 V! If the motor fails to rotate with live applied to the brown wire and neutral applied to the blue wire (brown wire connects conn ects to T3 on room stat s tat – calling, and the blue wire connects to T2 on room stat s tat – satisfied) then the motor has failed fail ed to operate Note: When the valve stops, the valve remains fully open as long as live is applied to the brown wire - The valve closes clos es under spring return when live li ve is removed from the brown wire - The valve may also be faulty if:

The orange wire only becomes live after the valve v alve has fully opened (grey wire must also be live) (Orange connects to L on the pump and boiler boil er only and grey wire connects to L terminal on time controller and L terminal on fused spur). If the boiler and pump continues to run when the cylinder stat and or room stat is satisfied when the time controller is in the OFF position. If using a 28m/m V4043H1106 zone valve on either hot water or heating circuits (S plan configuration only), the white wire is not needed n eeded and must be made electrically safe (cut back tight to black fly lead – no power wil l be on this wire).


44


Sequence of operation: (2 port valve – Honeywell V4043H) There are five wires to the valve: brown (live to syncron motor), orange (switched live to supply power to pump and boiler ), grey (permanent live to the micro switch), blue (neutral to syncron motor) mo tor) and green/yellow (earth). When there is a call for heat (via room stat or cylinder stat), power is sent down the brown wire which starts s tarts the motor. When the valve is open, op en, a micro switch is made via a cam and power is then sent to the boiler and pump via the orange wire (switched live). Power is constantly provided to the motor via v ia the brown wire, keeping the valve open, as long as there is a call for fo r heat. Once the call for heat is satisfied, satisfi ed, power comes off the brown, causing the motor to be de-energised. A spring then returns the valve to the closed position, closing the micro switch and disconnecting power to the orange wire, switching swi tching off the hot water or heating zone respectively. Note: If using a 28m/m V4043H1106 zone valve on either hot water or heating circuits (S plan configuration only), the white wire is not needed need ed and must be made electrically safe (cut back tight to black fly lead l ead – no power will be on this wire).

(3 port mid-position valve – Honeywell V4073A) There are five wires to the valve: white (from room thermostat calling for demand), orange (from cylinder thermostat calling for demand and switched live to supply power to pump and boiler), grey (from cylinder thermostat satisfied and H/W OFF of programmer blue (neutral (n eutral to syncron motor) and green/yellow (earth).


45


A typical Y plan schematic:


46


A typical S plan schematic:


47


Programmer - Be aware of 240 V! Always check the wiring, all the links are in place and that 240V on L and N is present on the back plate before suspecting a faulty programmer. programm er.

The programmer is faulty if: •

•

• •

If Live does not appear on HTG ON terminal when HTG only is selected (continuous or timed) Y plan and S plan (refer (r efer to diagrams) Live does not appear on HW OFF terminal when HW is off on programmer Y plan (refer to diagram) Live does not appear on HW ON terminal when HW only is selected (continuous or timed) Y plan and S plan (refer (r efer to diagrams)

Note: When a single channel time switch is on and calling for a demand but the motorised valve is not moving on the lever to switch on the boiler, then try linking the C (common) and ON (calling) connections together on programmer back plate. (Always isolate electrical power supply and remove fuse prior to this).

Should the zone valve motor across, then the programmer switching contacts are faulty. Should the zone valve remain the same, then further investigation is needed (syncron motor windings maybe burnt out or a seized valve spindle).


48


Motorised valve heads (diverter valves) Reasons a motorised valve head will fail to start: • • • •

Motorised valve head lead faulty Burnt out motor windings Motor axle/spindle seized Faulty printed circuit board

These devices are energised or de energised (via the printed circuit board) to operate a motorised axle/spindle. The movement of the motorised spindle communicates with the diverter valve via a bobbin assembly, controlling the path of heated primary water, either to the secondary plate exchanger or to the central heating circuit.

To test a motorised valve head lead:

240 V LIVE TEST Lead: Set multimeter to correct voltage scale and check at connections Test Central heating on:

Hot water on:

Result 240Vac between connections 1 and 2 25Vac-35Vac between connections 2 and 3 240Vac between connections 2 and 3 25Vac-35Vac between 1 and 2

Incorrect voltages maybe faulty printed circuit board or lead – needs further investigating. Correct voltages but motor axle not moving – replace motorised valve head


49


To test motorised valve head: Set multimeter to Ohms scale and measure coil coi l resistance: 0 Ohms between connections 1 and 3 9.6 K Ohms between connections 1 and 2 (res istance may vary) 9.6 K Ohms between connections 1 and 3 (res istance may vary) Motor axle retracts on hot water or hot water pre-heat facility – ok Motor axle visible on heating –ok


50


Diverter valves Reasons a diverter valve will fail to move • • • • • • • •

Wax capsule faulty Bobbin assembly faulty Faulty motorised valve head Seized push rod contaminated system water / blockages (magnetite) faulty pump faulty primary flow switch and / or microswitch microswi tch faulty printed circuit board

These devices, depending on the demand, controls the path of heated primary water either to the secondary heat exchanger (plate exchanger) or through to the central heating circuit. Diverter valves normally rest in central heating mode so it can dump excess heat on the central heating circuit.

To test a diverter valve

240 V LIVE TEST Central heating on: Check for correct voltage at end of wiring harness on motorised valve head (printed circuit board end – ensure correct colour wires are tested) Hot water on: Check for correct voltage at end of wiring harness on motorised valve head (printed circuit board end – ensure correct colour wires are tested) Note: Should correct voltages be present at respective re spective connections, but still not functioning correctly on a hot water water or central heating demand, then the diverter valve may need replacing.


51


Common faults On a central heating demand with the boiler firing but reaching up to temperature rapidly and shutting down with the pump running on, the diverter valve will be stuck in the hot water mode and needs replacing. On a hot water demand with the hot water temperature remaining cold but a temperature rise through the central heating flow pipe, the diverter valve will be stuck in the central heating mode. On a hot water demand with the hot water temperature remaining warm not hot, with a temperature rise through the central heating flow pipe, the diverter valve will be letting by.


52


Room thermostats Reasons a room thermostat will fail f ail to start • • •

Poor terminal connections Switch contact faulty Faulty timer/programmer

When the timer/programmer is on, it sends a signal to the room thermostat (this should then be live on the common terminal of the room thermostat). The room thermostat upon calling for heat will either turn on the boiler or energise a motorised valve. Should the common terminal read no voltage, vol tage, the timer/programmer must be further investigated.

To test a room thermostat

240 V LIVE TEST •

Set multimeter to correct voltage scale and check at connections (Checking for voltage on the terminals when at maximum and minimum dial settings, will ascertain the common wire, as it remains live during both these settings).

Turning the timer/programmer off with no voltage reading at the traced common terminal, will prove and complete this test. Should only one pair of wires be live when at maximum and minimum settings, then the room thermostat is faulty. A method to test the room thermostat where (1=Common ( 1=Common / 2=satisfied / 3=calling): Remove the wire from terminal 3 in room stat (calling) Ensure terminal 1 (common) is live Turn room stat to maximum setting so it is calling


53

Boiler FaultFinder Manual v2 Terminal 3 should now be live – if not, room stat is faulty Note: The Common, demand and satisfied terminals do vary on room thermostats, depending on make and model, where some will be terminal termi nal 3 for C, terminal 1 for demand and terminal 2 for satisfied. Others however, will be terminal 1 for C, terminal t erminal 3 for demand and terminal 2 for satisfied. (Generally there will be a small switching diagram inside the the outer casing of room thermostats for guidance purposes).

Common terminal: The “live in” terminal from the “central heating on” terminal of the programmer in most cases. Demand terminal: This contact will be “made” to the common when w hen the thermostat is calling or demanding heat. Satisfied terminal: This contact will be “made” to the common when w hen the thermostat has reached the required temperature or is satisfied.


54


Cylinder thermostats Reasons a cylinder thermostat will fail to start • • •

Poor terminal connections Switch contact faulty Faulty timer/programmer

When the timer/programmer is on, it sends a signal to the cylinder thermostat (this should then be live on the common terminal of the cylinder thermostat). The cylinder thermostat upon calling for heat turns on the boiler and/or energises a motorised valve. Should the common terminal read no voltage, the timer/programmer must be further investigated.

Common terminal: The “live in” terminal from the “hot water on” terminal of the programmer in most cases. Demand terminal: This contact will be “made” to the common when w hen the thermostat is calling or demanding heat. Satisfied terminal: This contact will be “made” to the common when w hen the thermostat has reached the required temperature or is satisfied.

To test a cylinder thermostat

240 V LIVE TEST •

Set multimeter to correct voltage scale and check at connections


55


•

•

(Checking for voltage on the terminals when at maximum and minimum dial settings, will ascertain the common wire, as it remains live during both these settings). Turning the timer/programmer off with no voltage reading at the traced common terminal, will prove and complete com plete this test. Should only one pair of wires be live when at maximum and minimum settings, then the cylinder thermostat is faulty.

Closed position (calling for heat) = 240V between common terminal (3) and calling terminal (1). Stat is faulty if terminal (1) does not become live when calling Open position (satisfied) = 240V between common terminal (3) and satisfied terminal (2). Stat is faulty if terminal (2) does not become live when satisfied Some models maybe marked C, NC and NO where NC is calling calli ng and NO is satisfied. Other models may be pre-wired where red is C, black is calling (NC) and yellow is satisfied (NO). Note: The Common, demand and satisfied terminals do vary on some cylinder thermostats, depending on make and model, where some will be terminal termi nal 3 for C, terminal 1 for demand and terminal 2 for satisfied.

Others however, will be terminal 1 for C, terminal t erminal 3 for demand and terminal 2 for satisfied. (Generally there will be a small switching diagram diagram inside the outer casing of room thermostats for guidance purposes). Terminals 3 (C) and 2 (NO) make on temperature rise. Terminals 3 (C) and 1 (NC) make on temperature falling.


56


Spark electrode(s) Reasons spark electrode(s) will fail to start • • •

• • •

Cracked ceramic insulation (causing leakage) Poor terminal connections Incorrect spark gap between electrode(s) or between electrode and burner/target Electrode tip damaged / corroded / eroded Damaged ignition leads Burnt out / failing spark generator

On some boilers, it may be difficult to visually see the ignition electrode(s) to ascertain if they are sparking correctly or even at all. Where this may be the case, always check the spark generator first for correct voltage readings (if possible, as not all boilers have remote spark generators, instead they are permanently fixed on the main p.c.b., where a new board will be required in this instance).

To test spark electrode(s)

240 V LIVE TEST • • • • •

•

Electrically isolate boiler / system controls Isolate gas supply beneath boiler Carefully remove spark electrodes from burner assembly With the gas left off, turn on electrical supply Ensure the electrode tips are pointed away from the burner area but the electrode base (near to lead connection) is touching the outer burner area to ensure adequate earthing Call for a hot water or central heating demand: demand :


57


Sparking occurs – May be faulty gas valve (needs further investigating)

No sparking occurs – • •

• •

Incorrect gap at electrode tips (commonly 3mm-5mm) Faulty spark generator (measure AC voltage across connections – will vary depending on manufacturer but should be in the region of 170 V AC or above) Faulty electrode leads (check continuity) Faulty electrodes (check continuity)

Note: If the gasket between the electrode elec trode base and the burner assembly appears to be worn / damaged when removing the electrodes for inspection, then both the gas supply and the electrical power supply must be isolated to prevent use – this would be AN A N IMMEDIATELY DANGEROUS SITUATION as products of combustion may enter the room.


58


Sequence of boiler operation: Central Heating Mode • • •

•

• • •

•

• • • •

•

•

•

Boiler in standby mode Demand called for via room thermostat/timer Pump runs – activating primary flow switch swi tch then micro switch above from NO to NC Diverter valve remains in at “rest” position (central heating port open only) Printed circuit board sends voltage to fan Fan runs ok Air pressure switch activates from C and NC position over to C and NO position (Sending signal back to Printed circuit board) Overheat cut out thermostat is checked for closed circuit (continuous (con tinuous circuit) Primary thermistor is also checked for correct thermal resistance Spark generator and ignition electrode(s) ok Gas valve energised and ignites ok (low rate) Flame detection electrode ok (sparking finishes – ionisation proved) Gas valve ramps up to range rated set pressure (Controlled via the thermistor and potentiometer at p.c.b) Boiler control thermostat or room thermostat is satisfied or the timer shuts down boiler Fan and pump over run continue to dissipate dis sipate residual heat (over run time will vary) Boiler returns to standby mode

Hot Water Mode • •

Boiler in standby mode Demand called for activating hot water flow switch then micro switch above from NO to NC (paddle, turbine, wheel or pressure differential type)


59

•

•

Boiler FaultFinder Manual v2 Pump runs-activating primary flow switch then micro switch above from No to NC Diverter valves internal hydraulics moves over from “rest” position (central heating port open) to domestic hot water position posi tion (port to secondary plate exchanger open only) Note: not all models incorporate a diverter valve and plate to plate heat exchanger, but instead utilise a twin pass main heat exchanger

• • •

•

• • • •

• •

•

Printed circuit board sends voltage to fan Fan runs ok Air pressure switch activates from C and NC position over to C and NO position (sending signal back to Printed circuit board) C/H and H/W overheat cut out thermostats are checked for closed circuit (continuous circuit), primary and secondary thermistors are also checked for correct thermal resistance, Spark generator and ignition electrode(s) ok Gas valve energised and ignites ok (ignition rate) Flame detection electrode ok (sparking finishes – ionisation proved) Gas valve modulates according to the water flow rate/ desired temperature setting (controlled via the thermistor and potentiometer at p.c.b) Boiler shuts down when hot water demand is satisfied Fan and pump over run continue to dissipate dis sipate residual heat (over run time will vary) Boiler returns to standby mode

Please note: The above sequence of operation for both hot water and central heating are not identical for every boiler out there, however, the sequence of events will not progress any further forward, if there are no feedback signals or if they are incorrect.


60


Electrical safety checks Whether you are fault finding, servicing or commissioning an installation, these five preliminary electrical checks are paramount to establish if the appliance is safe to work on.

Mains voltage test (dead test) This test isolates the power supply serving the boiler, so as safe, further testing can be continued, without the risk from stray electrical currents causing a shock. •

•

Electrically isolate power supply at fused spur switch and remove fuse (Always ensure the boiler is fused at 3 amps on completion of work) Set multimeter to correct voltage scale (above 240V AC) and check L and N at the boiler terminal block

This should read zero volts, the boiler is now no w safe to work on.


61


) t s e t d a e d ( : t s e t e g a t l o v s n i a M


62


Earth continuity test (dead test) This test will ascertain whether the earth continuity between the earth supply to the boiler and the internal component earth connections and the metal casing of the boiler are earthed correctly. •

• •

Electrically isolate power supply at fused spur switch and remove fuse. (Always ensure the boiler is i s fused at 3 amps on completion of work) Set multimeter on ohms scale for resistance readings First put black lead from multimeter to the retaining screws of the fused socket connection and then the red lead from the multi meter to the boiler casing.

The resistance reading must be no more than 1 ohm and whenever the resistance reading proves to be more than 1 ohm, there is a fault present and must be traced and rectified before proceeding any further. Check all the earth wires for continuity and check all connections are secure. Warning Poor earth continuity or no earth continuity at all will create a dangerous situation, as any metal parts that should be earthed may become live and a short circuit may cause an electric shock


63


) t s e t d a e d ( : t s e t y t i u n i t n o c h t r a E


64


Short circuit (dead test) This test will ascertain the integrity of the internal resistance of the boil er and should read no resistance/infinity between L and N on the 3 amp fused plug top pins. • •

Set multimeter on ohms scale for resistance readings First put black lead from multi meter to N pin on the boiler terminal strip and secondly put the red lead from the multi m ulti meter to the L pin on the boiler terminal strip

Should the resistance reading move, there is a dead short and a fault is present. Where the boiler supply is connected to a fused double pole switch, it should be isolated at the ring main supply end, to eliminate any possible, further faults present on the circuit. (This is why a 3 pin plug is a much better option as a double pole spur can cause further problems). There are six internal boiler components to check and the L and N connections for each component must be removed individually and then the L and N at the 3 pin plug top or at the boiler terminal block bl ock must be measured again.

Components to check (in this sequence): • • • • • •

Pump Fan Gas valve Diverter valve Circuit board Internal wiring loom (visual observation only)

Should the internal resistance measure infinity/no resistance when the component is disconnected, then the faulty component has been traced. Should the resistance reading maintain moving when the component is disconnected, the dead short is elsewhere (further investigation needed in the above sequence). (c) 2014 BoilerFaultFinder

65


) t s e t d a e d ( t i u c r i C t r o h S


66


Resistance to earth (dead test) This test confirms the integrity (resistance) of the insulation between L and E on the boiler terminal strip or plug top pins (Black lead firstly to E pin and red lead secondly to L pin). Where the boiler supply is connected to a fused double pole switch, it should be isolated at the ring main supply end, to eliminate any possible, further faults present on the circuit (This is why a 3 pin plug is a much better option as a double pole spur can cause further problems). With the boiler switches, time switches and thermostats on and the multimeter set on ohms scale, the resistance reading between L and E should read no other than O L ( infinity ) and if so, there is a fault . A detailed continuity check is required to trace the faulty component before proceeding any further.


67


) t s e t d a e d ( : h t r a e o t e c n a t s i s e R


68


Mains voltage and polarity tests This test will ascertain the correct polarity between L and N although, some boilers will operate unaffected by reversed polarity. •

• • •

Connect boiler to power supply via 3 pin plug top or inserting 3 amp fuse into switch Ensure boiler is on but with all controls off, so there is no demand Set multimeter to correct voltage scale on V AC AC Firstly put the black lead from multi meter to the E terminal block on the boiler and and secondly the red lead from multi meter meter to the N terminal block on the boiler – this should s hould read 0V AC, but up to 15V AC is ok

Note: Should a reading be greater than 15V AC, A C, this indicates a fault is present within the house wiring, but the polarity at the fused switch should first be checked, prior to calling an (NICEIC) approved electrician.


69


d e u n i t n o c s t s e t y t i r a l o p d n a e g a t l o v s n i a M


70


240 V TEST •

• • •

Connect boiler to power supply via 3 pin plug top or inserting 3 amp fuse into switch Ensure boiler is on but with all controls off, so there is no demand dem and Set multimeter to correct voltage scale on V AC AC Firstly put the black lead from multi meter to the E terminal block on the boiler then secondly the red lead from multi m ulti meter to the L terminal block on the boiler - this should read approx. 240V AC


71


d e u n i t n o c s t s e t y t i r a l o p d n a e g a t l o v s n i a M


72


240 V TEST • • •

Ensure boiler is on but with all controls off, so there is no demand Set multimeter to correct voltage scale on V AC AC Firstly put the black lead from multi meter to the N terminal block on the boiler then secondly the red lead from the multi meter to the L terminal block on the boiler – this should also read approx. 240V AC


73


d e u n i t n o c t s e t y t i r a l o p d n a e g a t l o v s n i a M


74


General fault finding Noisy heat exchanger (‘kettling’ and/or banging) Magnetite / rust blockages in waterways Pump head failing (not at full capacity) Boiler control thermostat faulty (causing overheat stat to trip)

chemical cleanse system replace pump head replace thermostat

Noisy pump Trapped air Impellor out of alignment

vent system and pump replace pump head

Noisy fan Worn bearings Jammed air rotor impeller heavy with foreign matter accumulation

replace fan lubricate rotor clean / service fan

Explosive ignition pilot assembly not positioned correctly faulty gas valve (over gassing) faulty gas valve (sticking armature) partially blocked burner faulty ignition electrodes

reposition assembly check burner pressures replace solenoid / gas valve clean / service burner inspect gap(s)/condition


75


Pressure relief valve opening / pressure gauge continuously climbing undersized expansion vessel valve faulty or seat contaminated with sludge plate to plate heat exchanger faulty (fractured) filling loop faulty / passing pressure expansion vessel diaphragm has perished expansion vessel has lost air charge Pump head failing (not at full capacity) Boiler control thermostat faulty (causing overheat stat to trip) faulty gas valve (over gassing)

upgrade vessel size replace valve replace plate exchanger replace / cap off replace vessel re charge vessel replace pump head replace thermostat check burner pressures

Noisy solenoid check mounting replace solenoid replace solenoid

loose mounting return spring loose faulty solenoid

Noisy hot water flow switches faulty mechanism (loose internal paddle or wheel)

replace switch

Burner not igniting faulty thermocouple faulty gas valve (sticking armature) faulty ignition electrodes / leads faulty printed circuit board blocked injector gas at meter or boiler off

check connections / replace thermocouple replace solenoid / gas valve inspect gap(s) / condition replace circuit board check injector check isolation valves


76


Radiators warm up when hot tap opens / central heating flow pipe very hot with hot with radiators hardly getting temperature rise faulty diverter valve (faulty wax capsule or bobbin assembly)

replace valve

Radiators warm up when no hot tap is open and the timer is in the off position (timer working correctly) domestic hot water micro switch stuck in NC position

replace dhw micro switch

Fan running but no ignition at electrodes air pressure switch hoses loose split / kinked hoses water in hoses (condensation) reversed pressure connections (hoses wrong way around) split/punctured air pressure switch diaphragm damaged combustion chamber seals cracked pilot window or damaged seal faulty air pressure micro switch flue / airway ducts blocked at terminal faulty fan (not at full capacity)

ignition electrodes cracked ignition wiring harness damaged / loose faulty spark generator on p.c.b. ignition electrodes gap too far apart

check ports and firmly fix remove kink / replace hose dry hoses / replace hoses correctly connect hoses replace air pressure switch replace entire seal replace glass / seal replace air pressure switch clear restrictions/blockages check/ lubricate bearings clear debris build up blocked / melted venturi replace fan assembly check / replace electrodes check wiring / connections replace p.c.b. check gap (as per manufacturer’s instructions)


77


Boiler shuts down and goes to lockout faulty pump (not at full capacity) faulty fan (not at full capacity)

blocked condensate pipe work/trap faulty ionisation electrode blocked heat exchanger (blocked with sludge) blocked primary filter on plate exchanger faulty thermistor (losing calibration) faulty overheat cut out stat (losing calibration) faulty gas valve (faulty modureg / solenoid) blocked bypass pipe/ no bypass faulty air pressure switch (stuck in NO position) faulty low water pressure switch (losing calibration) excess air trapped within heat exchanger

replace pump head check / lubricate bearings clear debris build up replace fan assembly clear blockage / ice plug or Increase pipe work fall check gap/wiring /damages replace or cleanse system clean debris from filter check / replace check / replace replace gas valve adjust / install bypass replace air pressure switch

Check / replace air vent


78


Domestic hot water fault finding When the hot water is ok but the central heating is not, this eliminates all operating sequence possible faults such as the fan, air pressure switch, pump, ignition sequence, ignition detection, gas valve and domestic hot water thermistor. Therefore, the fault can only be at the diverter valve, micro switch, flow switch, central heating thermistor, high limit cut out thermostat, printed circuit board and external controls (room thermostat and timer).

No domestic hot water • • • • •

• • • • • • • • •

split diaphragm on flow switch (pin not moving) blocked pressure differential pipes (scale deposits) faulty micro switch (burnt out contacts) faulty motorised valve head (burnt out windings) diverter valve (diverter may be stuck in central heating mode, spindle seized, dhw micro switch stuck in NO position) programmer (faulty switching contacts) loose connection / faulty cylinder thermostat faulty zone valve (seized, burnt motor, end switch) faulty mid-position valve (seized at port B) severely blocked plate exchanger (scale and sludge) faulty printed circuit board (hot water side) faulty thermistor (open circuit / infinity) faulty high limit cut out thermostat (open circuit / infinity) faulty pump (not at full capacity)

Domestic hot water too hot • • • • • •

cylinder thermostat set too high or out of calibration cylinder thermostat stuck in closed (calling) position cylinder thermostat is loose faulty thermistor and high limit cut out burner pressure too high faulty gas valve (c) 2014 BoilerFaultFinder

79


Domestic hot water not hot enough • • • •

• • • • • • • •

blocked primary and/or secondary heat exchanger (scale and sludge) flow restrictor not fitted (as recommended by manufacturer) cold mains pressure/flow rate too high faulty diverter valve (diverter may be letting by through central heating port) faulty thermistor or scaled burner pressure too low undersized gas installation pipe work faulty gas valve cylinder thermostat out of calibration faulty pump (not at full capacity, dissipating the heat) hot water inlet strainer (if fitted) blocked blocked primary filter on plate exchanger (not applicable to all boilers) (Should the temperature differential between the flow and return thermistor be too great, the boiler will modulate down and even cut out. A classic example is when the hot water temperature fluctuates!


80


Central heating fault finding When the central heating is ok but the hot water is not, this eliminates all operating sequence possible faults such as the fan, air pressure switch, pump, ignition sequence, ignition detection, gas valve and central heating thermistor. Therefore, the fault can only be at the diverter valve, micro switch, flow switch, domestic hot water thermistor, high limit limi t cut-out thermostat, domestic hot water heat exchanger and printed circuit board.

No Central Heating • • • • • • • • • • • • •

split diaphragm on flow switch (pin not moving) faulty micro switch (burnt out contacts) faulty motorised valve head (burnt out windings) diverter valve (faulty wax capsule or bobbin assembly) faulty programmer (faulty switching contacts) faulty room thermostat stuck in the open (satisfied) position faulty zone valve (seized, burnt motor, end switch) faulty mid-position valve (seized at port A) severely blocked heat exchanger (scale and sludge) faulty printed circuit board (central heating side) faulty thermistor (open circuit / infinity) faulty high limit cut out thermostat (open circuit / infinity) faulty pump (not at full capacity)

Central Heating Too Hot • • • • •

room thermostat set too high or out of calibration room thermostat stuck in closed (calling) position faulty thermistor and high limit cut out burner pressure too high faulty gas valve


81


Central Heating Not Hot Enough • • • • • • • • • • •

blocked heat exchanger (scale and sludge) blocked radiators / pipe work (scale and sludge) return manifold filter blocked (debris) faulty diverter valve faulty thermistor or dirty burner pressure too low faulty gas valve room thermostat out of calibration range rating potentiometer set too low for heat load dip switches on printed circuit board not at maximum temperature faulty pump


82


Top tips •

•

•

It sometimes pays to test the air pressure hoses with (LDF) Leak detection fluid, when encountering ignition problems. (Hoses maybe split or have loose connections). Where the air pressure switch is difficult to access (which is most common), test at the end of the wiring harness harnes s (at the p.c.b. end), which will also test the integrity of the C, NC and NO wiring also. When the automatic air vent on the boiler shows sho ws signs of severe s evere leakage through the threaded bleed cap, it is not always a fault with the air vent itself, despite the fact of sludge being present within the system water. Check the pressure charge at the expansion vessel, vessel , as the air vent is a much weaker component than most under pressure pr essure and releases the build up which the vessel should be taking up, but cant due to a loss in air. Always isolate boiler at flow and return valves valve s and depressurise via the pump vent cap (using an absorbent towel or similar), never the pressure relief valve as this may encounter debris d ebris on the seat and then drip constantly. Better still, utilise the drain off valve val ve connected to the hydraulic block (where fitted). Pre-charge vessel as shown on data badge (typically between 0.5 – 1.0 bar) and re-pressurise boiler via filling loop. Open isolation valves (these may start to leak) and monitor pressure gauge and air vent. Should water maintain leaking from air vent, then a direct replacement repl acement in necessary, however, should the pressure gauge remain under 2.5 bar (when hot) with no leaks, then the air vent is i s ok.


83


Always run a hot water demand when a central centr al heating fault exists, as this will then eliminate several components from being defective. (Fan, pump, flame detection electrodes, gas valve, thermistors and hot water side of p.c.b. – all being ok). Faults can only then rest with (diverter valve being seized/sticking, s eized/sticking, faulty primary flow switch and/or micro switch, swi tch, faulty primary thermistor or p.c.b). The same process applies for a hot water fault!

•

When an internal expansion vessel is beyond repair (the diaphragm has perished as water is entering the pre charge section and the press ure gauge climbs up to 3 bar and discharges water via blow off of f pipe), install a remote vessel on the return pipe as close cl ose to the boiler as possible. possi ble. Remember – it may be the case that the existing vessel vess el is not adequately sized due to the customer extending the size of their heating system over the years! Always oversize the remotely fitted vessel if not n ot sure and purge the system water from the abrasive particulates (iron oxide), oxi de), by way of flushing with good quality chemical cleanser and inhibitor. inhi bitor. (Heavy corrosion build up may m ay have been the reason why the rubber diaphragm perished).

•

Always photograph and manually log / record the boiler gas council (GC) number and serial number when working on boilers which needs attention to parts - if possible. possib le. (Manufacturers have the right to change their internal component design at time of mass production, without you even knowing). This will be hassle when the wrong part turns up, leaving you the embarrassment, but more importantly, your customer without a working boiler for longer periods – not good for promoting your professional and reliable services.


84


NEVER PRE-EMPT THE PART NUMBER IN THE SHORTS PARTS LIST SECTION OF THE INSTALLATION & SERVICING MANUAL WILL BE CORRECT! •

•

•

•

During winter months (especially frosty conditions), should the boiler ignite but remain sparking and then the burner goes out almost suddenly, the condensation pipe maybe blocked from an ice plug forming. (The ionisation / flame detection electrode maybe linked to the condense trap via a linked wire which when exposed to water, will short out the connection and behave like the electrode is not sensi ng the presence of a flame – hence the repetitive ignition pattern). When sparking occurs but no ignition takes place (flow switches, air pressure switch, thermistors, fan, diverter valve, high limit cut out stat and pump – all being ok). The fault can only then t hen rest with the gas valve or p.c.b). When replacing dry pocket thermistors or high limit cut out thermostats, always use heat conductive paste between the interconnecting surfaces to ensure good thermal conductivity. When boiler is not functioning on either hot ho t water or central heating but the power is shown to be on, always check to see if the manual overheat cut out stat has been activated (open circuit). These can be seen on top of boiler casing, below the boiler casing or within the boiler clamped onto pipes, where the button will wil l be raised and you will be able to press down to reset (closed circuit). Do not ignore this problem – further investigation needed (see boiler shuts down within fault finding section).

•

When encountering stiff moving fan impellors / seized rotors, WD 40 is not a permanent solution to the problem, and it must be pointed out that WD 40 is designed to degrease (clean) and not lubricate.


85


•

When measuring in low voltage DC with multimeter on components such as modureg gas valves and multi speed fans, but with no steady reading present, then the transformer on the printed circuit board may be faulty. When boiler is intermittently firing up and extinguishing with the radiators getting hot, (with no hot tap running or the central heating timer activated), it maybe the domestic hot water tap micro switch is stuck in the NC position and not necessarily a faulty diverter valve. When the diverter valve is in its rest position, po sition, it leaves the central heating port open, and when the domestic hot water micro switch is stuck in the NC position (calling for a demand), the boiler thinks a hot water draw off has occurred, but due to the pressure differential flow switch (attached on top of the diverter valve) not actually moving mov ing the spindle / diverter assembly within, the boiler fires f ires up and heats the radiator circuit due to the open port in its rest position. Should there be continuity between C and NC (with ( with no hot water demand), then the micro switch needs replacing.


86


Safe use of multimeter functions •

•

• • • • •

• • • •

AC – (Alternate current) will show a wavy line l ine with dots diagonally opposite or ACV. DC – (Direct current) will show a straight line li ne with dots below or DCV. (measures a steady reading). Typical ranges for digital multimeters are: DC Voltage: 200mV, 2000mV, 20V, 200V, 600V AC Voltage: 200V, 600V DC Current:200 A, 2000 A, 20mA, 10mA OHMS scale will show an uppercase omega symbol of Ω. (Resistant of movement).

Resistance: 200Ω, 2000Ω, 20KΩ, 200KΩ Continuity buzzer will show the symbol of ⁾⁾⁾. (buzz = closed circuit / continuous circuit / zero resistance) (no buzz = open circuit / no continuous circuit / infinity / OL).

Black test lead always goes into COM terminal on multimeter mul timeter (first). Red test lead always goes into V Ω or ACV or V~ terminal on multimeter (second). Always select voltage range above 240 as less than this will read off the scale when measuring for mains voltage and never rotate the dial while the meter is connected to a circuit – you may rotate it through a current range, short circuiting the probes and damaging either the meter or the circuit. When measuring across L and N parts of a circuit (motor windings), windings ), a reading of zero resistance indicates a fault (short circuit). The resistance readings in motor windings will vary (pumps, fans, solenoids, transformers). When measuring closed switches (micro switches, overheat cut out stats) a reading of zero resistance (closed circuit / continuity) = ok. When measuring open switches (micro switches, overheat cut out stats) a reading of infinity / OL (open circuit / no continuity) = ok. (c) 2014 BoilerFaultFinder

87

Boiler FaultFinder Manual v2 When measuring in volts AC the black test lead must first be connected to E or N connections and then secondly the red test lead be connected to the L connection, which then completes the circuit. All electrical test equipment used should be suitable for the electrical tests being carried out and any leads / probes to be inspected before use to ensure it is safe. Respect the circuitry you are working on - If you touch exposed metal, or cause a short circuit, or connect to high voltage, you may expose yourself to a serious hazard. Although more expensive, an auto ranging multimeter is far easier as it automatically adjusts its range to give a meaningful reading. Some of the ranges typically displayed on a multimeter will rarely be used, if at all by gas engineers. The main ranges typically used are AC, DC and continuity – keep it si mple rule! The gas operative should ensure they have sufficient knowledge of the test equipment capabilities and functions so as to be able to conduct electrical testing in a safe manner.

WHERE ANY DOUBT EXISTS – ALWAYS FOLLOW MANUFACTURERS SAFETY INSTRUCTIONS.


88


Boiler servicing procedure – the professional’s approach •

•

•

•

•

•

•

•

•

Always introduce yourself politely and have your ID card on show, this will only reassure your customer that you are a registered regis tered member of Gas Safe and this is always a professional professi onal attitude to practice. First impressions always count to a new customer! Ascertain from customer any problems (if (i f any) they may be experiencing. Carry out a visual risk assessment of the gas installation pipe work, gas meter / box and any sealing, other appliances, system sys tem controls and any ventilation provisions needed. Carryout gas tests (let – by, tightness and governor operating pressure). Inform the customer of any findings findin gs and immediately address any findings which may constitute a danger to life or property in accordance with the current industry standards. Electrically isolate appliance and turn programmer / timer to on, room thermostat to maximum setting and boiler thermostat to maximum maxim um setting. Electrical safety checks (earth continuity, resistance to earth, short circuit and mains voltage polarity). Before commencing to strip down appliance, ensure very briefly, both hot water and heating is functioning correctly. Electrically isolate the appliance and remove fuse.


89


•

•

•

•

•

•

•

•

•

•

Remove burner and clean off any oxidation / debris d ebris accumulation using a soft brush, can of compressed air and hoover. Inspect condition of combustion seals (they MUST be in i n good condition). Inspect heat exchanger connections for signs of any leakage and brush clean the waterways using correct grade heat exchanger brush and hoover. Inspect fan assembly and clean off any dirt / debris accumulation using a soft brush, can of compressed air and hoover. (The fan may need to be removed when there is heavy accumulation present, as it can imbalance the impellor –always handle with care!). Carry out a visual assessment assess ment of the integrity of flue pipe, connections and termination. (Flues concealed within boxing in need access points)! Replace components previously removed for inspecting / cleaning and test. Some boilers may need the condense trap removed for cleaning. Undertake necessary flue flow continuity test / spillage test (open flue appliance only). Check all combustion case seals, especially on a positive fan assembly, using a tapered match. (Any leakage due to worn seals, the appliance MUST not be further used and the immediately immediatel y dangerous procedure applied. THEY ARE STILL OUT THERE! Open all trv`s to maximum setting (if fitted). Check minimum and maximum gas setting pressures (if possible) and inlet working pressure. Check co/co2 readings with electronic combustion combus tion gas analyser.


90

Boiler FaultFinder Manual v2 (modern boilers will need to be forced into “service mode” for this procedure – follow manufacturer’s instructions). •

•

•

•

•

•

Monitor the system water pressure gauge to ascertain if the correct vessel pre-charge is ok or if there is a faulty diaphragm. Visually inspect all internal parts for any signs of leakage. Vent system to remove any trapped hydrogen gas / air build b uild up. (Hydrogen gas is a by product of electrolytic corrosion corrosi on – FLAMMABLE!). Attach service sticker to appliance showing next due service date and contact details (remember, the property may change hands but if not, it will be another satisfied customer). Ensure property has been left clean and tidy and as you found fou nd it. Finally, discuss with the customer any possible energy efficient system improvements you think they could benefit from, by adding onto their existing system. Always look at it as your responsibility resp onsibility to raise their awareness in these matters as it can only maintain a positive and professional relationship, which should lead to more work.

Common improvements / upgrades are new trv`s, power flush system, new room thermostat, new timer / programmer, insulated copper cylinder, cylinder thermostat, insulated pipe work.


91


Maximising condensing operation There is now a requirement in the Domestic Building Services Compliance Guide that states that where condensing boilers are installed, the system should be designed to operate at lower temperatures to give a return water temperature less than 55 degrees C to maximise maximi se condensing operation.

Background: When natural gas burns, it produces considerable quantities of water and this is vaporised in the combustion process (converted to steam). This process absorbs quite a lot of energy (heat), in fact, approximately 14% of the heat produced by burning the gas is required to boil off the water – this heat is commonly known as latent heat, as it causes a change of state – from liquid to gas (steam). Question: So why do we need to get the return water wa ter temperature less than 55 degrees C in order to maximise condensing operation?

Answer: The design of a condensing boiler enables a lot of this latent heat to be recovered by condensing the steam in the flue gases back to water (condensate), but this can only be achieved by getting the return water temperature down to 54 degrees C – the dew point of gases. At this temperature, the water vapour in the flue gases will start to condense onto the heat exchanger and give up its latent heat. This heat, plus the sensible heat recovered through cooling the flue gases, can amount to around 12% of the heat that would have otherwise been lost. Reducing the return water temperature still further will recover even more latent heat. Whilst commissioning your boiler replacement, you may have heard the boiler condensing through the plastic pipe leading to the drain within only minutes of (c) 2014 BoilerFaultFinder 92

Boiler FaultFinder Manual v2 operation, as the return water temperature is well below 55 degrees C on start-up from cold. As the flow temperature gradually increases and approaches the boiler thermostat set point – approximately 82 degrees C, the burner will commence modulating down to low flame as it begins to match the heat load upon it, which may also switch off if a light heat load is put upon it. At this point, the return water temperature is likely to be approximately 70 degrees C and possibly higher. Limiting the return water temperature to around 55 degrees C means we must limit the flow water temperature to approximately 66 degrees C. With underfloor heating, where lower flow water temperatures can be used at the manifolds, weather compensation controller settings can be changed so that the maximum water temperature is 66 degrees C when the outside temperature is say - 2 degrees degrees C. Changes in the external external temperature alter the temperature of the flow, lowering it if the outside temperature rises and increases it if it drops. The constant monitoring of the external climate means the boiler is able to operate efficiently at the minimum required temperature and condense for longer. With outside weather compensation controls, there is always a provision for running at maximum boiler flow temperature for domestic hot water heating, and this should be on a priority basis. basi s. The optimum efficiency level that many newly installed condensing boilers can achieve is not being fully recognised. Domestic heating accounts for around 14% of the UK`s CO2 emissions, the installation of intelligent weather compensation controls could help to reduce r educe it by almost a quarter. When installing radiators within new or refurbished properties which are insulated to current high standards, you can do exactly the same thing, but you need to oversize the radiators so that they will give gi ve the required heat output.


93

Boiler FaultFinder Manual v2 Identify the difference between room temperature required and the mean radiator water temperature, which determines the rate at which heat from the water can be transferred to the room. This determines the value of the Delta T factor which is used to adjust the rated output of the radiator from the manufacturer’s catalogue rating. Once calculated, multiply the manufacturers stated radiator output by the corresponding Delta T factor to show the actual performance of the radiator in those specific conditions. Flow water temperature Return water temperature System temperature drop Mean water temperature Room temperature Temperature difference

66 degrees C 55 degrees C 11 degrees C 60 degrees C (Flow temp. – System temp. Drop divided by 2) 20 degrees C (Mean water temp. – Room temp.)

Delta T factors for radiator- to- room temperature differences (figures may vary slightly depending on manufacturer):

Temperature difference (degrees C) 30 35 40 45 50 55 60 65 70 75

Delta T factor 0.423 0.512 0.605 0.700 0.798 0.898 1.000 1.104 1.211 1.319

Example: Heat emission required:

2000 Watts (2 KW) (c) 2014 BoilerFaultFinder

94

Boiler FaultFinder Manual v2 Room air temperature required: Mean water temperature in radiator:

20 degrees C 60 degrees C

1. Temperature difference 60 – 20 = 40 degrees C 2. From delta T factor table 40 degrees C 0.605 3. Divide the required heat emission by factor 2000 watts (2KW) required divided by 0.605 = 3305 watts (3.3KW) 4. From the manufacturer’s selection table, choose the radiator rated at 3305 watts (or slightly more).


95


Programmer and time switch compatibility guide Programmers do vary in their settings/functions and the differences di fferences are as follows: 24 hour programmer – one set of times all week • 5/2 day – one set of times for week days/ another set se t of times for • weekends (but weekend times may be set the same as for w eekdays). 7 day – different times for each day of the week. we ek. •

There are two types of programmer: Mini programmer The hot water mode can be switched on without the heating mode, but in order to switch on just the central heating, the hot water will also simultaneously come on with it. (This will be common on gravity hot water systems with fully pumped heating). The temperature of the domestic hot water can reach very high temperatures in this arrangement, as whilst the heating is on, gravity convection currents take place and cycles until heating is satisfied via room thermostat or more commonly the boiler thermostat. Should a temperature rise occur within the radiators during the summer months whilst on hot water mode only, then the anti-gravity valve (fitted on central heating flow pipe) may be faulty “letting-by”.

Full programmer The hot water mode and heating mode can be switched on totally independent from one another or both modes can be on at the same time. (This will be common on fully pumped systems). Some two channel programmers will share the time base (common time base) which means both hot water and heating must mu st share the same on/off periods. (c) 2014 BoilerFaultFinder

96

Boiler FaultFinder Manual v2 The following compatibility guides are a quick and easy reference tool to upgrade and replace existing programmers and time switches to Drayton models, indicating the respective time base (24 hour, 5/2 day or 7 day) and respective terminal comparisons (E, N, L, H/W ON/OFF, C/H ON/OFF). Simply look through the existing makes and models within the faulty programmer sections or within the faulty time switch sections and the "Boiler Fault Finder" will show all recommended Drayton replacements. Then simply look through the programmer or time switch terminal comparison tables to ascertain the necessary back plate wiring conversion. conversio n. Please note: In the event of removing any existing programmer, it is paramount to make note of the wire colours, the terminal positions and the numbers in relation to the existing back plate.

You may find the existing faulty programmer or time switch model has been discontinued, however, by using this guide, it will indicate the suitable replacement. Some recommended replacement models maybe a direct plug in replacement without any disturbance to the wiring, some models may need simple minor wiring conversion and some models may need both the back plate and the wiring changed. The manufacturer must be consulted at all times if there is any doubt whatsoever.


97


24 hour programmer compatibility guide Existing make and model: Danfoss Randall 102, 102E, 922, 3020P, 3060, 4033, SET2, SET2E, SET3, SET3E, SET3M, CP15, CP715, CP715 SI, FP15, FP715, FP715 SI, MP15 Suitable replacements for above: LP112 (Electronic, linked H/W & C/H – common time base) LP241 (Electronic, independent H/W & C/H) LP241 SI (Electronic, independent H/W & C/H) SM2 (Electromechanical)

Existing make and model: Drayton TEMPUS 3 & 6 Suitable replacements for above: LP112 (Electronic, linked H/W & C/H – common time base) LP241 (Electronic, independent H/W & C/H) LP241 SI (Electronic, independent H/W & C/H) SM2 (Electromechanical)

Existing make and model: Honeywell ST699, ST6200, ST6300, ST9400A, ST9400S Suitable replacements for above: LP112 (Electronic, linked H/W & C/H – common time base) LP241 (Electronic, independent H/W & C/H) LP241 SI (Electronic, independent H/W & C/H) SM2 (Electromechanical)

Existing make and model:Horstmann 525, Centaur Plus C21, Diadem, H21, H121, TC1, Tiara Suitable replacements for above: LP112 (Electronic, linked H/W & C/H – common time base) LP241 (Electronic, independent H/W & C/H) (c) 2014 BoilerFaultFinder

98

Boiler FaultFinder Manual v2 LP241 SI (Electronic, independent H/W & C/H) SM2 (Electromechanical)

Existing make and model:Myson MEP2C Suitable replacements for above: LP112 (Electronic, linked H/W & C/H – common time base) LP241 (Electronic, independent H/W & C/H) LP241 SI (Electronic, independent H/W & C/H) SM2 (Electromechanical)

Existing make and model:Potterton Myson MINIMINDER, 2000 Suitable replacements for above: LP112 (Electronic, linked H/W & C/H – common time base) LP241 (Electronic, independent H/W & C/H) LP241 SI (Electronic, independent H/W & C/H) SM2 (Electromechanical)

Existing make and model:Siemans/Landis&Staefa RWB200 Suitable replacements for above: LP112 (Electronic, linked H/W & C/H – common time base) LP241 (Electronic, independent H/W & C/H) LP241 SI (Electronic, independent H/W & C/H) SM2 (Electromechanical)

Existing make and model:Sunvic SP50, MP2, SELECT 207 Suitable replacements for above: LP112 (Electronic, linked H/W & C/H – common time base) LP241 (Electronic, independent H/W & C/H) LP241 SI (Electronic, independent H/W & C/H) SM2 (Electromechanical) (c) 2014 BoilerFaultFinder

99


5/2 day programmer compatibility guide Existing make and model:Danfoss Randall 102E5, CP15, CP75, CP715, CP715 SI, FP7, FP15, FP715, FP715 SI, FP975, MP15, MP75, SET5 Suitable replacements for above: LP522 (Electronic, independent H/W & C/H) LP522 SI (Electronic, independent H/W & C/H)

Existing make and model:Drayton TEMPUS 4,6,7 Suitable replacements for above: LP522 (Electronic, independent H/W & C/H) LP522 SI (Electronic, independent H/W & C/H)

Existing make and model:Honeywell ST6450 Suitable replacements for above : LP522 (Electronic, independent H/W & C/H) LP522 SI (Electronic, independent H/W & C/H)

Existing make and model:Myson MEP2C Suitable replacements for above: LP522 (Electronic, independent H/W & C/H) LP522 SI (Electronic, independent H/W & C/H)

Existing make and model:Potterton Myson EP2001, 2002 Suitable replacements for above: LP522 (Electronic, independent H/W & C/H) LP522 SI (Electronic, independent H/W & C/H)

Existing make and model:Siemans/Landis&Staefa RWB9, RWB252 Suitable replacements for above: LP522 (Electronic, independent H/W & C/H) LP522 SI (Electronic, independent H/W & C/H)


100


Existing make and model:Sunvic SELECT 207 Suitable replacements for above: LP522 (Electronic, independent H/W & C/H) LP522 SI (Electronic, independent H/W & C/H)


101


7 day programmer compatibility guide Existing make and model:Danfoss Randall 102E7, 972, CP15, CP75, CP715, CP715 SI, FP75, FP715 SI, FP975, MP75, Suitable replacements for above: LP722 (Electronic, independent H/W & C/H) LP722 SI (Electronic, independent H/W & C/H)

Existing make and model:Drayton TEMPUS 7 Suitable replacements for above: LP722 (Electronic, independent H/W & C/H) LP722 SI (Electronic, independent H/W & C/H)

Existing make and model:Honeywell ST6400, ST9400C Suitable replacements for above: LP722 (Electronic, independent H/W & C/H) LP722 SI (Electronic, independent H/W & C/H)

Existing make and model:Horstmann 527, CENTAUR TC7, CENTAUR PLUS C27, H27, Suitable replacements for above: LP722 (Electronic, independent H/W & C/H) LP722 SI (Electronic, independent H/W & C/H)

Existing make and model:Myson MEP2C Suitable replacements for above: LP722 (Electronic, independent H/W & C/H) LP722 SI (Electronic, independent H/W & C/H)

Existing make and model:Potterton Myson EP3000, 3002, 6000, 6002 Suitable replacements for above: LP722 (Electronic, independent H/W & C/H) (c) 2014 BoilerFaultFinder

102

Boiler FaultFinder Manual v2 LP722 SI (Electronic, independent H/W & C/H)

Existing make and model:Siemans/Landis&Staefa RWB9, RWB270 Suitable replacements for above: LP722 (Electronic, independent H/W & C/H) LP722 SI (Electronic, independent H/W & C/H)

Existing make and model:Sunvic SELECT 207, SP100 Suitable replacements for above: LP722 (Electronic, independent H/W & C/H) LP722 SI (Electronic, independent H/W & C/H)


103


24 hour time switch compatibility guide (All the following Danfoss suitable replacement time switches have Volt – free contacts, making them suitable for combi boilers).

Existing make and model:Danfoss Randall 103, 911, SET1, SET1E, TS15, TS715, TS715 SI, Suitable replacements for above:

LP111 (Electronic) LP111 SI (Electronic) SM1 (Electro mechanical)

Existing make and model:Drayton TEMPUS 1 Suitable replacements for above:


Existing make and model:Honeywell ST6100A, ST9100A, ST9100S Suitable replacements for above:


Existing make and model:Horstmann CENTAUR SC1, CENTAUR PLUS C11, CORONET, H11 Suitable replacements for above: LP111 (Electronic) LP111 SI (Electronic) SM1 (Electro mechanical)

Existing make and model:Myson MEP1C Suitable replacements for above:


Existing make and model:Potterton Myson EP 4000 (c) 2014 BoilerFaultFinder

104

Boiler FaultFinder Manual v2 Suitable replacements for above:


Existing make and model:Siemans/Landis&Staefa RWB30, 50, 100 Suitable replacements for above:


Existing make and model:Sunvic SP20, SELECT 107 Suitable replacements for above:



105


5/2 day time switch compatibility guide Existing make and model:Danfoss Randall 103ES, SET4, TS15, TS715, TS715 SI, TS75, TS975 Suitable replacements for above:

LP711 (Electronic LP711 SI (Electronic)

Existing make and model:Drayton TEMPUS 1, 2 Suitable replacements for above:

LP711 (Electronic) LP711 SI (Electronic)



Existing make and model:Potterton Myson EP 40001, 4002 Suitable replacements for above:


Existing make and model:Siemans/Landis&Staefa RWB152 Suitable replacements for above:


Existing make and model:Sunvic SELECT 107 Suitable replacements for above:



106


7 day time switch compatibility guide Existing make and model:Danfoss Randall 103E7, 971, TS75, TS715, TS715 SI, TS975 Suitable replacements for above:


Existing make and model:Drayton TEMPUS 2 Suitable replacements for above:


Existing make and model:Honeywell ST6100C,ST9100C Suitable replacements for above:


Existing make and model:Horstmann CENTAUR SC7, CENTAUR PLUS C17, H17, 517 Suitable replacements for above:




Existing make and model:Potterton Myson EP 5002 Suitable replacements for above:



107


Existing make and model:Siemans/Landis&Staefa RWB170 Suitable replacements for above:


Existing make and model:Sunvic SP35, SELECT 107 Suitable replacements for above:



108


Programmer terminal comparisons Make

Model

Drayton lifestyle

LP112,LP241, LP522, LP722,LP241 SI,

Drayton

LP522 SI, LP722 SI SM2

E

N

L

H/W OFF

C/H OFF

H/W ON

C/H ON

N

L

1

2

3

4

N

L

1

2

3

4

The following makes and models need to be cross referenced to the above for wiring comparisons (Some of the following existing models may be discontinued but replace with the above models)

ACL

MP(TOWERCHRON) FP (TOWERCHRON)

2 2

1 1

Switchmaster

400,600 (NO CONNECTION TO TERM.4 ON 600)

N

L

Drayton British Gas Danfoss Randall

805,900,900I EMP2, UP1 CP15,CP715,FP15,FP715,CP71 5SI, FP715SI

N N

L L

N

L

E E

7 7

6 6

E

5

E E E E

3020P,3060 4033(LINK 1-6) 102,102E,102E5,102E7(LINK63) 701(LINK L-5 AND 5-6) 702(LINK L-5 AND 5-6) 922,972 (LINK L-2 AND 2-5) SET2,SET2E,SET3E,SET3M,FP9 75, SET5 (LINK L-2 AND 2-5)

11

6

10

4

3

1

4 1

2 2

3 3

1 4

1

2

3

4

4

4 3

2 2

6

1

2

N N N

L L L

4 1

2 4

3 3 3

1 1 6

N

L

3

6

1

4

N

L

7

4

6

3


8

5

109


Make

Model

Drayton lifestyle

LP112,LP241, LP522, LP722,LP241 SI,

Drayton

LP522 SI, LP722 SI SM2

E

C/ H OF F

H/ W ON

C/ H ON

N

L

H/ W OFF

N

L

1

2

3

4

N

L

1

2

3

4

The following makes and models need to be cross referenced to the above for wiring comparisons (Some of the following existing models may be discontinued but replace with the above models)


110

Boiler FaultFinder Manual v2 Honeywell

Horstmann

Myson

Potterton Myson

ST699/799 (LINK L-5 AND 5-8) ST6200,ST6300,ST6400,ST645 0 ST6400S,ST9400A/C,ST9400S ST9500C ST7100 (LINK L-3 AND 3-6) 525,527,425DIADEM,H21,H27 ,H121 TIARA (LINK L-2 AND 2-5) CHANNEL PLUS H21XL,H27XL,H27ZXL CENTAUR PLUS C21,C27 MICROTIMER (LINK L-5 AND 5-8) MEP2C

E

N

L

1

2

3

4

N

L

7

4

8

5

N

L

3

6

1

4

N

L

1

2

3

4

N

L

7

4

6

3

N

L

1

2

3

4

N

L

1

2

3

4

N

L

1

2

3

4

N

L

1

2

3

4

Siemens/Lan dis & Staefa

ALL EP200`S,EP3000`S,EP6000`S (LINK L-5 AND N-N) MINIMINDER MINIMI NDER RWB2,RWB2E,20,40,102,200, 252,270

Sunvic

RWB9,RWB29 SELECT 207

N

L

1

2

3

4

SP50,SP100 (LINK L-3)

N

L

1

4

2

5


111


Time switch terminal comparisons

Make

Model

E

L

C O M

O N

OFF

SPARE

Drayton lifestyle

LP111,LP711,LP111SI,L P711SI

N

L

1

3

2

4

Drayton

SM1

N

L

1

3

2

4

The following makes and models need to be cross referenced to the above for wiring comparisons (Some of the following existing existing models may be discontinued but replace with the above models) ACL

TC (TOWERCHRON)

2

1

4

7

Switchmaster

300,980

N

L

4

1

Drayton

TEMPUS 1 AND 2

N

L

1

3

2

4

British Gas

EMT2,

N

L

1

3

2

4

UT1

N

L

1

3

2

4

N

L

1

4

2

5&6

N

L

1

4

2

3 1,2,3

Danfoss Randall

TS15,75

E

TS715,TS715SI

Honeywell

TS975

E

N

L

5

4

6

SET1, SET1E

E

N

L

5

4

6

SET4

E

N

L

5

4

6

103,103E,103E5,103E7 103,103E,103 E5,103E7

4

5

6

3

1

911,971

E

N

L

5

6

4

ST6100A,ST6100C,ST61 00S,ST9100A,ST9100S 00S,ST9100A,S T9100S

N

L

1

4

2

ST7000B

N

L

1

2

3


2 2

4

112


Make

Model

E

L

C O M

O N

OFF

SPARE

Drayton lifestyle

LP111,LP711,LP111SI,L P711SI

N

L

1

3

2

4

Drayton

SM1

N

L

1

3

2

4

The following makes and models need to be cross referenced to the above for wiring comparisons (Some of the following existing existing models may be discontinued but replace with the above models) Horstmann

CENTAUR SC1,SC7

L

3

2

N

L

4

6

N

L

2

4

3

N

L

2

4

3

E

N

L

3

4

E

N

L

5

4

6

MEP1C

N

L

3

4

2

Potterton Myson

EP4000,4001,4002,500 2

N

L

5

4

2

Siemens / Landis & Staefa

RWB3,

N

L

4

3

RWB27,RWB30,RWB50 ,100,152,170

N

L

2

4

3

N

L

2

4

3

SELECT 107

N

L

1

3

2

4

SP20,SP35

N

L

3

5

4

5

CHANNEL PLUS H17XL, H11XL CENTAUR PLUS C11,C17 EMERALD423,PEARL AUTO 517,CORONET,H11,H1 7

Myson

MICROTIMER (LINK L-5 AND 5-8)

RWB7

Sunvic

E

E


113


Asbestos – the hidden dangers! dangers! Asbestos components may take the form of seals, seals , gaskets, insulation panels and rope within old appliances, especially aged boilers. boil ers.

There are three types normally encountered in the UK: • • •

Chrysotile (white) Amosite (brown) Crocidolite (blue)

These are usually referred to as their common names (shown above in brackets), although they cannot be identified by their colour. Laboratory analysis is needed for positive identification. Asbestos fibres enter the body through breathing, via the nose and mouth. They cannot enter the body through the skin or via food and drink as this will pass through. Disease is caused by tiny fibres of asbestos passing into the lungs where they can stay for many years. Small but repeated exposure on different jobs over time can lead to the development of an asbestos-related disease, which can take anything from 15 to 60 years to develop.

THIS IS WHY IT IS CRUCIAL TO PREVENT EXPOSURE ON EVERY JOB! If in doubt or suspect asbestos – STOP WORK IMMEDIATELY! The following list has been compiled to aid you and minimise the risk from exposure, however, the list cannot be considered to be definitive, and any material you do suspect as asbestos should be treated as such. There may be other appliances containing asbestos materials that do not appear on the list. Specialist advice should be sought from the manufacturer prior to commencing any work and where necessary, specialist licensed asbestos removal companies used.


114


Boilers known to contain asbestos Manufacturer

Model

Caradon Ideal

concord companion Mexico Super CF 100 Mexico Super CF 125 Mexico Super CF 140 Mexico Super CF30/40 Mexico Super CF30/40 Mexico Super CF40 Mexico Super 40/50 Mexico Super CF40/60 Mexico Super CF40/60 Mexico Super CF50/60

G.C. Number

Components

44-392-21

G, R

41-407-46

MF

41-407-48

MF

41-421-39

MF

41-415-26

MF

41-415-05

MF

41-407-20

MF

41-421-49

MF

41-415-27

MF

41-415-06

MF

41-421-50

MF

Keys to components that contain asbestos (where known): G – Gaskets I – Insulation T – Tape

MF – Mastic containing Fibres R – Rope SW – Sealing Washers


115


Manufacturer Caradon Ideal

Model Mexico Super CF 55 Mexico Super CF 65 Mexico Super CF 75 Mexico Super CF80 Mexico Super RS 100 Mexico Super RS125 Mexico Super RS30/40 Mexico Super RS30/40 Mexico Super RS40 Mexico Super RS40/50 Mexico Super RS40/60

G.C. Number

Components

41-407-22

MF

41-407-40

MF

41-407-42

MF

41-407-44

MF

41-415-05

MF

41-407-49

MF

41-415-24

MF

41-415-03

MF

41-407-19

MF

41-421-47

MF

41-415-04

MF




116


Manufacturer Caradon Ideal

Model Mexico Super RS50/60 Mexico Super RS55 Mexico Super RS65 Mexico Super RS75 Mexico Super WRS 430 Mexico Super WRS440 Mexico Super WRS450 Mexico Super WRS460

G.C. Number

Components

41-421-48

MF

41-407-21

MF

41-407-41

MF

41-407-43

MF

41-407-53

R, M F

41-407-54

R, M F

41-407-55

R, M F

41-407-56

R, MF




117


Manufacturer Gloworm

Model Space saver 20-30 RF Space saver 30-40 RF Space saver 50-60 RF Space saver 50 BF Space saver 38 BF Space saver 75 BF Space saver 38 CF Space saver 52 CF Space saver 75 CF Space saver 45-60 OF Space saver 45-60 BF Space saver 22-30 B Space saver 22-30 OF Fuel saver 12 CF Fuel saver 12 RS Fuel saver 15 CF Fuel saver 15 CF2

G.C. Number

Components

41-313-86

*

41-313-87

*

41-313-89

*

41-315-27

*

41-315-31

*

41-315-32

*

41-315-44

*

41-315-45

*

41-315-46

*

41-315-63

*

41-315-64

*

41-315-69

*

41-313-70

*

41-047-05

*

41-047-04

*

41-047-03

*

41-047-09 Fuel saver

*


118


Manufacturer Gloworm

Model G.C. Number Components 15 RS 41-047-02 * Fuel saver 15 RS2 41-047-08 * Fuel saver 18 RS 41-047-12 * Fuel saver 20 RS 41-047-06 * Fuel saver 25-30 41-315-80 * Fuel saver 25-30B 41-315-79 * Fuel saver 30-40 41-315-82 * Fuel saver 30-40B 41-315-81 * Fuel saver 40-50 41-315-84 * Fuel saver 40-50B 41-315-83 * Fuel saver 55-60B 41-315-85 * Fuel saver 60-70B 41-315-87 * Fuel saver 9 CF 41-047-11 * Fuel saver 9 RS 41-047-10 * Fuel saver 60-70B 41-315-87 * Fuel saver 9 CF 41-047-11 * Fuel saver 9 RS 41-047-10 * *Various components have been known to contain co ntain asbestos within these boilers, and for this reason, cannot be disclosed in the list. (c) 2014 BoilerFaultFinder

119


Manufacturer Potterton Myson

Model Flamingo 50 BF WM Flamingo CF 20-30 Flamingo CF 50 Flamingo RS 13 Flamingo 50 BF WM Flamingo CF 20-30 Flamingo CF 50 Flamingo RS 13 Flamingo Rs 13 Flamingo Rs 20-30 Flamingo RS 40 Flamingo RS 50 S Kingfisher 180&120 Kingfisher 180&220

G.C. Number

Components

41-601-14

G, I

41-601-33

G, I

41-601-18

G, I

41-601-06

G, I

41-601-14

G, I

41-601-33

G, I

41-601-18

G, I

41-601-06

G, I

41-601-12

G, I

41-601-23

G, I

41-601-25

G, I

41-601-43

G, I

41-601-19

G, I

41-601-20

G, I




120



Model Kingfisher 180 CF Kingfisher 220 CF Kingfisher CF100 Kingfisher CF125 Kingfisher CF150 Kingfisher CF40 Kingfisher CF 40A Kingfisher CF45 Kingfisher CF50 Kingfisher CF50 A Kingfisher CF55 Kingfisher CF60 Kingfisher CF60

G.C. Number

Components

41-605-80

G, I

41-605-81

G, I

41-605-42

G, I

41-605-15

G, I

41-605-16

G, I

41-605-57

G, I

41-605-60

G, I

41-605-07

G, I

41-605-58

G, I

41-605-61

G, I

41-605-08

G, I

41-605-56

G, I

41-605-38

G, I




121

Boiler FaultFinder Manual v2 Manufacturer Potterton Myson

Model Kingfisher CF80 Kingfisher CF90 Kingfisher RS 100 Kingfisher RS 50 Kingfisher RS 60 Kingfisher RS 80 Netaheat 10/16 Netaheat 16/22 Netaheat 6/10 Netaheat MK 1 BF 10/16 Netaheat Mk 1 BF 16/22 Netaheat MK 2 10/16

G.C. Number

Components

41-605-39

G, I

41-605-40

G, I

41-605-59

G, I

41-605-48

G, I

41-605-37

G, I

41-605-41

G, I

41-605-67

G, I

41-605-66

G, I

41-605-68

G, I

41-605-03

G, I

41-605-04

G, I

41-605-10

G, I




122



Model Netaheat MK 2 16/22 Netaheat MK 2 F 10/16 Netaheat MK 2 F 16/22

G.C. Number

Components

41-605-11

G, I

41-605-34

G, I

41-605-35

G, I




123


Manufacturer Vaillant

Model Combicompact VCW 242 E Combicompact VCW 282 E T3W VCW Sine 18 T3W VCW Sine 20/1 T3W VCW Sine 25/1 Combicompact VCW 221 Combicompact VCW 240 Combicompact VCW 280

G.C. Number

Components

47-044-13

SW *

47-044-18

SW *

47-044-01

SW

47-044-03

SW

47-044-05

SW

47-044-14

SW *

47-044-15

SW*

47-044-16

SW*

Note: Appliances marked (*) pre 1991 Keys to components that contain asbestos (where known): G – Gaskets I – Insulation T – Tape



124


Notching and Drilling requirements in joists when 1st fixing When notching or drilling structural timbers, it is crucial that the holes/notches are made in such a way that does not compromise the integrity of the structure. On new build sites and large developments, any installer intending to notch/drill holes in structural timbers must first seek permission from the architect, structural engineer and/or supervising officer for the building. Notches and holes in simply supported floor joists should be cut no deeper than 1/8 of the depth of the joist. They should not be cut closer to the support than 0.07 times the span, nor further further away than 0.25 (1/4) of the span. It is essential that structural members are not weakened by indiscriminate notching and boring. In this respect, both the size and positioning must be in accordance with the diagrams shown below.


125


Requirements for notching traditional joists Span (L)

0.25 x L

Depth (D)

Max depth of notch = D/8

0.07 x L Rules for joist depth up to 250mm. For deeper joists assume D = 250mm

Notches should be in this zone


126


Requirements for drilling holes through traditional joists Span (L)

Holes should be located in this zone and drilled at the neutral axis

0.4 x L 0.25 x L

Depth of joist (D)

Maximum diameter of a hole = 0.25 x D Neutral axis of joist Not less than 3 diameters apart centre to centre

Drilled holes should be no greater in diameter diamete r than ¼ of the depth of the joist. jois t. They should be drilled on a neutral axis and should not be less than three diameters apart, measured from centre to centre. Drilled holes should sh ould be located in the area between 0.25 and 0.4 times the span of the joist joi st from the support.


127


Engineering joists Buildings that incorporate timber “I” joists (engineering joists) allow for more flexible drilling of holes for pipework. I joists incorporate 38mm knockouts (dependent upon the manufacturer), and also allow for larger holes to be drilled through the joists. The same rule applies when drilling through I joists as for drilling traditional joists where horizontal measurements between holes are concerned. However, as the strength of I joists is in the flange, these joists are not suitable for notching, as notching the flange will damage the structure of the joist, which will have a detrimental effect on its strength. The size and positioning of holes drilled through I joists must be in accordance with the diagram shown below. Not less than 3 diameters apart centre to centre

38mm diameter knockouts are incorporated in TJI joists at approx 300mm centres

Flange

Flange

Web Additional holes can be cut but leave minimum 3mm of web at top and bottom


128


Example: (Refer to previous diagrams for clarity):

Notching traditional joists •

•

•

•

For a traditional joist (150mm deep x 50mm wide and spanning 3000mm): Minimum distance from supporting wall = 3000mm x 0.07 times the span = 210mm Maximum distance from supporting wall = 3000mm x 0.25 times the span = 750mm Maximum depth of notch = 150mm / 8 = 18.75mm

Therefore, notching may occur between 210mm and 750mm from fro m the supporting wall, and notches should be no deeper than 18.75mm.

Drilling holes through traditional joists •

•

•

•

For a traditional joist (150mm deep x 50mm wide and spanning 3000mm): Minimum distance from supporting wall = 3000mm x 0.25 times the span = 750mm Maximum distance from supporting wall = 3000mm x 0.4 times the span = 1200mm Maximum hole diameter = 150mm / 4 = 37.5mm

Therefore, holes can be drilled at the neutral axis between 750mm and 1200mm from the supporting wall. The maximum hole diameter should not exceed 37.5mm and holes should not be located less than three diameters apart (centre to centre), meaning 37.5mm holes should shoul d be separated


129


A Typical Service & Repair Engineer’s Toolkit Hand tools Small adjustable spanners Pump pliers (small, medium and large) 1000V rated electrical screwdriver set 1000V rated electrical nose pliers Selection of TORX head bits & holder Microbore pipe bender Adjustable pipe cutter Soldering equipment Pair of earth continuity bonding leads Hydraulic pressure vessel hand pump Digital pressure vessel checker Stopwatch Telescopic inspection mirror Telescopic magnet Electronic combustion gas Analyser & printer Differential digital manometer Differential digital thermometer Water flow rate weir gauge Electronic gas leak detector Digital multimeter with fused leads Battery powered volt stick Selection of heat exchanger brushes Smoke match holder Very soft paint brushes (1” and 2”) Telescopic inspection camera Infra red temperature gun (c) 2014 BoilerFaultFinder

130

Boiler FaultFinder Manual v2 Braided filling loop hose Filling loop keys (Worcester Bosch) Long posi-drive screw driver Small LED torch Pump head allen keys (4mm & 6mm) Selection of allen keys Sharp Stanley knife Sharp paint scraper Clean dust sheets (for carpet) Engineers maintenance mat (worktops) Henry Hoover Air vent sizing gauge Fuse kit (quick blow and 3amp type) Fibre washer kit (various sizes) Boiler first aid kit (various nuts, screws and bolts) notice) Smoke pellet holder Fire extinguishers (water,CO2 & dry powder)

Consumables Purimachos FJC non setting compound Strikes smoke matches Hayes orange smoke pellets abrasive cleaning strips ROCOL gas seal compound ROCOL LDF (leak detection fluid) ROCOL air dusting cans PTFE tape (gas & non-gas types) Gas ON/OFF identification tape ROCOL gas tap lubricant heat conductive paste Hoover bags PRS 10 approved closure tape (c) 2014 BoilerFaultFinder

131

Boiler FaultFinder Manual v2 silver foil tape absorbent paper towels silicone lubricant grease silicone lubricant spray back to black coal spray water regulation approved jointing compound spare neoprene manometer hose

Up to Date Pocket Reference Guides tightness testing & purging terminals and terminations ventilation slide rule gas rating slide rule Gas Industry Unsafe Situations Procedure WLAR (warning labels - AR) WLID (warning tags – ID) CP3 (chimney/hearth notice plate) WL5 (gas emergency control valve label) WL8 (compartment/ventilation label) WL9 (electrical bonding label) WL16 (electrical isolation warning tag)

Forms / Labels CP1 (gas safety record) CP14 (warning / advice CP3 (chimney/flue/fireplace & hearth pad)

THIS LIST CANNOT BE CONSIDERED TO BE DEFINITIVE OR BY ANYWAY IN ORDER, HOWEVER, IT DOES COVER MOST OF WHAT A PROFESSIONAL WILL


132


NEED WHEN CARRYING OUT SERVICE AND REPAIR WORK WITHIN THE FIELD. THIS LIST HAS BEEN COMPILED TO ASSIST THOSE WHO ARE NOT AS EXPERIENCED AS OTHERS AND MAY NOT SEE THESE ITEMS AS SO OBVIOUS.


133



134

Boiler FaultFinder Manual v2 Subscribers(2)

Recommend Documents