Scotsman NU150 Service Manual page 25

NU Undercounter Ice Machine Service Manual
Trouble shooting table
Symptom
Irregular cubes
size & some cloudy
Decreased ice
capacity
Unit doesn't defrost
or no ice
Incorrect discharge
pressure
Excessive water on
unit base
Possible Cause
Spray pipe blocked
Shortage of water
Machine unlevel
Water temperature sensor failure Replace the water temperature sensor
Inefficient compressor
Water valve leak
Spray pipe blocked
Non-condensable gas in system
Bad ventilation
Too much dust on air filter
Expansion valve partially blocked Check, if damage, replace it
Defrost valve leaking
Refrigerant over charge
Shortage of refrigerant
Discharge pressure too high or
too low
Defrost valve blocked or not
open
PC board Failure
Defrost valve not opening
Water inlet solenoid valve not
opening
Inoperative condenser sensor
Too much or less
refrigerant, or non-refrigerant gas
was charged
Inoperative PC board
Water system leak
Suggested Correction
Clean the spray pipe
See the
water-shortage
Level the machine as required
Replace the compressor
Check, if damage, replace it
Check, if blocked, clean it.
Vacuum and re-charge
Improve ventilation or put the machine
to the good ventilation place
Clean the air filter, if needed, replace it.
Change
slowly
Vacuum and re-charge according to the
nameplate
Check for the cause of incorrect
discharge pressure
Check, if damage, replace it
Check, if damage, replace it
Check, if damage, replace it
Check, if damage, replace it
Check, if damage, replace it
Check whether the refrigeration system
charged is leakage
Vacuum and re-charge according to the
nameplate and the requirement from
Scotsman Company
Check, if damage, replace it
Check for the leaking points and repair
it. If necessary, replace it.
24
Trouble Shooting Tabl
processing method
charged volume,
for
release