Service Diagnosis - Scotsman AF300 User Manual

AF300
Service Diagnosis: Condition - No Ice Being Produced
STATUS: ICE MAKER DOES NOT OPERATE
A. Check : Voltage to the unit, restore it if there is none. Compare to the nameplate. If the voltage is
correct and the unit will not start, go to B.
B. Check : The master switch , switch ON if off. If the unit does not start go to C.
C. Check : The reset switch , (high pressure): depress and release the high pressure reset switch. If the
unit still does not start, go to D.
The pressure control opens at 400 PSIG (+ or - 30). Normal operation: water cooled - water will flow from
the condenser drain; air cooled - the fan blade turns and pulls hot air out of the machine. On water cooled,
if the water supply was turned off, the unit will possibly trip on high pressure.
If the unit trips out on pressures below 370 PSIG, replace the control.
D . Check that the bin thermostat is closed. If open with no ice on it, turn thermostat knob CCW, if this
does not close the thermostat, replace it. If the thermostat is closed and the unit will not start, go to E.
E . Check the water pressure to the unit. The machine will not run if there is not enough water pressure.
Restore/adjust water supply. If the unit will not start with good water pressure, go to F.
F. Check the low pressure cut out. If the low pressure control is closed, go to G. If it is open, it could be
due to :
Very low ambient temperatures
Low refrigerant charge
The auger not turning
Restricted system
Check the low side pressure, the low pressure cut out opens at pressure below 4 psig. If open it may be
due to: a. the evaporator is too cold, because the auger was not turning when the unit was refrigerating; b.
there is not enough refrigerant; c. there is a restricted system. Check a, b, or c. below.
If a. Check the coupling, if it's turning and the auger isn't, replace the coupling. If the coupling is not
turning, remove the gearbox and check for internal damage, repair and replace in the machine.
If b. Check for low charge, add some refrigerant, if the unit will operate, (normal low side pressure being
about 29 psig) stop and look for a leak, repair, replace the drier, evacuate, and weigh in the nameplate
charge.
If c. Check for a restricted system, replace the drier, evacuate, and weigh in a nameplate charge.
G . Check that the Auger Delay contacts 3-2 are closed. If open, and the low side (suction) pressure is
over 40 PSIG, replace the auger delay pressure control. If contacts 3-2 are closed, and the unit will not
start, go to H.
H . Check: The gear motor , if it will not run, the compressor will not run. If there is power to the auger drive
motor, and it does not run, replace the auger drive motor. If the motor operates, but the compressor will not
start, go to I. Note: The gearmotor may not go to full speed if the evaporator bearings are worn or the
evaporator needs cleaning.
I . If the gearmotor operates, but the compressor contactor coil does not have power, check the
centrifugal switch. If the contactor coil does have power but does not pull in, replace the contactor. If all
of the above check out, there will be power to the compressor.
January 1993
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