Certificate of Competency - 5 General Engineering Knowledge FRESH WATER GENERATOR TROUBLESHOOTING
Problem
Cause
Consequence
Act ion
Drop in production
Partially blocked
scaling of heat
Dismantle
due to lower
fead water orifice
exchanger plates
evaporator
boiling temperature
and / or sludge
on vapor side
section and clean
and lower t over
deposits on hot
evaporator and
evaporator
water side
orifice
Drop in production
sludge on the heat
Dismantle
due to higher
exchanger plates on
condenser section
boiling temperature
the sea water side
and then clean
Production drop
Inlet channel
Dismantle
due to lower boiling
in evaporator /
evaporator,
temperature and
condenser plate
condenser section
higher t over
stack blogged, eg:
and clean
evaporator /
with rust scales,
condenser
gasket, fragments
and lower t over condenser
etc et c Too low ejector
Not sufficient
See instructions
pump pressure
flow to condenser
for low flow ejector
section and
pump, below
ejector L ea ka g es
L ow v a cu um
Ca r r y o ut a p re s su r e test at max. 150
Production drop
kPa(1.5 kp / cm 2 )
due to low vacuum
(21.8 PSI)
(normal vacuum above 90%)
Foreign bodies in ejector nozzles
Bl o c ki n g
I n sp ec t n oz zl es , and clean, replace nozzles, if damaged.
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Certificate of Competency - 5 General Engineering Knowledge Too high back
Pr odu ct ion dr op
Ch ec k ov er bo ar d
pressure downsteam
pipe and valves for
of ejector. Max 60
blocking / function
KPa (0.5 kp / cm2)
ability
(8.7 PSI) Non return valve in
Replace non-return
air extraction pipe
valve
defect
Problem
Cause
Consequence
Action
Too low ejector
Not sufficient
See “Sea cooling
pump pressure
flow to condenser
water flow”
section and ejector Air in condenser
Production drop
vent condenser
Too high back
Pr odu ct ion dr op
Ch ec k ov er boa rd
pressure downsteam
pipe and valves for
of ejector max
blocking/function
60kPa(0.6,kp/ cm 2)
ability
(8.7 PSI) Leakages
Low vacuum
Carry out a pressure test at max. 150 kPa(1.5 kp/cm 2 ) (21.8 PSI)
Production due to high boiling
Foreign bodies in
temperature
ejected nozzles
Blocking
Inspect nozzles, and clean. Replace nozzles, if damaged
Too low ejector
Pressure gauge
Clean or replace
pump pressure.
defect
power gauge
Minimum pressure 300 kPa(2.0 kp/ cm2) (43.5 PSI)
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Certificate of Competency - 5 General Engineering Knowledge Suston strainer
No sufficient
Clean suction
blocked
pressure and
strainer
flow to condenser section and ejector Valves on suction or
see above
pressure pipe defect
Examine and overhaul defective valves
Leakages from
see above
Repair
see above
Check pump
suction pipe to pump Impeller/seal ring defective
maximum clearance is 1.0mm
Pump rotating in
see above
Interchange phases
wrong direction Warm or incorrect
Replace nozzle
injector nozzle Air pockets in steam
Discrete steam
arrangement
arrangement and evaporator section
Too low fresh
steam pressure
See “technical
water production
Incorrect
specification” and
due to incorrect
adjust pressure
temperature on the
accordingly
circulated heating
Incorrect back
Check whether
water
pressure in
actual back pressure
condensate
on condensate line
discharge pipe
corresponds with max back pressure on installation (PI) diagram. See “technical drawings”
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Certificate of Competency - 5 General Engineering Knowledge Problem
Cause
Consequence
Action
Suction pipe
produced
Check suction pipe
leakage.
freshwater
especially unions
escapes
and connections,
overboard through
repair.
ejector Mechanical seal in
see above
freshwater pump
Replace mechanical seal
defect Impeller / seal
see above
Sight glass overflow. ring in fresh water
Check pump. Max clearance 0.9mm.
extraction pipe defect Pump rotating in
see above
Interchange phases
wrong direction Valves to freshwater
Check all valves
tank closed Inlet filter for water
see above
Clean filter
clock blocked Production drop
Defective water
Examine water
according to water
clock
clock. Let the
clock. In spite of
produced water flow
normal pressure and
through water clock
temperature and
into a 10
no visible overflow
and check
in sight glass and
production with a
vacuum pipe
stop watch
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Certificate of Competency - 5 General Engineering Knowledge Demister not fitted
Dumping of
Check the demister
correctly
produced
is fitted against
freshwater
baffle and front cover
Front cover gasket
Replace front cover
defect or not fitted
gasket
correctly Insufficient brine
High brine level
See separate
extraction
(normal level 10 –
instructions for
20 mm).
insufficient, brine extraction, below.
electrode unit
Examine electrode
defective or dirty
unit for cracks. Check that is fitted
Salinity too high
correctly. Clean if
(more than 2.0
necessary.
ppm).
leakage in
Open distiller
condenser section
and pressure test condenser. Max.600 kPa (6.0 kp/ cm 2 ) (87 PSI). If there is a defective plate, remove together with adjacent plate assemble plate stack according to new plate number with reduced assembly measurements. Check plate gaskets and replace, if necessary.
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Certificate of Competency - 5 General Engineering Knowledge Problem
Cause
Consequence
Action
Ejector pump
High boiling
See special
pressure too low
temperature, low vacuum. Salinity higher than 2.00
instructions for too low ejector pump pressure, above.
ppm Foreign bodies in
see above
ejector nozzles
Check nozzles, and clean. Replace damaged nozzles
Insufficient brine extraction-brine
Too high back
level in sight glass
pressure downstream
higher than 20 mm.
of ejector Wrong dimension of
see above
Examine overboard pipe and valves
see above
feedwater orifice
Examine office dimensioncheck technical specification
Non-return valve in brine suction pipe of
see above
Examine valve and repair, or replace
ejector defect Leakage in evaporator section
Frequent refit of freshwater expansion tank due to lose of hot water
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Open distiller and pressure test condenser. Max. 600 kPa (6.0 kp/ cm 2 ) (87 PSI). If there is defective plate, remove together with adjacent plates assemble plate stack according to new plate number with reduced assembly measurements. Check plate gaskets and replace, if necessary.
Certificate of Competency - 5 General Engineering Knowledge Ejector nozzles
High boiling
defective
temperature, low
Replace nozzles
vacuum Wrong dimension
Check dimensions
of feedwater inlet
on spare parts list.
orifice Abnormal amperage consumption of
Bearings in motor
High temperature
Examine with
defective
in motor ends,
stethoscope, and
and exercise
replace bearings, if
noise
defective
Frequent motor
Examine and
stops
replace contactor
ejector pump motor Contractor defective
set, if defective Breaking of phases
See above
Max. 5% difference in amperage between phases
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