Service Diagnosis - Scotsman FME504 Installation Manual

NME454, 654 & FME504, 804

SERVICE DIAGNOSIS

Symptom
No ice is made, nothing operates
No ice, auger motor is turning
Unit makes ice, but very slowly.
Possible Cause
Unit off due to no power
Unit off due to master switch in OFF
position.
Unit off due to low water level.
Unit off due to ice level sensors
(photo-electric eyes) blocked.
Unit off due to scale on water level
sensor.
Unit off due to high pressure control
open.
Auger motor hums but does not turn. Auger can't turn. Circuit board has not
Unit is shut down
Low pressure control open
No power to circuit board.
Circuit Board gear motor relay will not
close
Water level or ice level sensor failed. Check, replace sensor
Compressor contactor coil is open
Compressor will not start
Circuit board compressor relay will
not close.
High discharge pressure because of a
dirty condenser
Low capacity because the auger and
evaporator are coated with mineral
scale
Low suction pressure due to low
refrigerant charge
January 2007
Page 22
Probable Correction
Restore Power
Switch master switch to ON.
Check water supply, filter, strainer,
float valve. Correct water supply.
Check/clean ice level sensors.
Clean water level sensor.
Check for water interruption (water
cooled) or fan motor failure (air cool).
yet shut unit down.
Circuit board has shut ice machine
down due to high auger motor amp
draw. Check for cause of high amp
draw, including bearings, gearmotor
condition and scale on auger and in
evaporator.
Auger not turning due to: motor
failure; auger relay failure on circuit
board; or gears stripped. Check drive
train.
TXV restricted or not metering. Check
bulb temperature.
Lack of refrigerant. Check for leak.
Check for a restricted system
Check harness
Hi or low pressure cut outs open
Check, replace board
Check/replace contactor
Check start capacitor.
Check start relay
Check compressor windings
Check, replace board
Clean the air filter and condenser.
Clean the water system
Locate leak. Recover refrigerant,
repair leak, replace dryer, evacuate
and weigh in the nameplate charge