Scotsman ND750 Service Manual page 20

ND750
SERVICE DIAGNOSIS: Condition - No Ice Being Produced
STATUS: GEARMOTOR OPERATES, COMPRESSOR DOES NOT
A. Check the compressor relay.
The relay is on the circuit board, if it does not supply power to the contactor coil, the
compressor will not run.
1. Check for power at the contactor coil, if none:
a. Check for power at the compressor relay at the circuit board.
If there is power at the relay, but none at the contactor coil,
Check for an open wire between the relay and the contactor.
2. Check the contactor coil. If the coil is open, replace the contactor.
3. Check the auger drive motor centrifugal switch. If, when the drive motor is running,
contact 4 (black wire removed) has no power, and all of the above switches have been
checked, replace the centrifugal switch, or the drive motor.
4. If the compressor relay on the circuit board has power on the NO contact, but not on the COM contact,
replace the circuit board
B. Check the compressor
1. Check the compressor start relay.
2. Check the start capacitor.
3. Check the windings of the compressor for open windings or shorts to ground.
Replace those items found defective.
January, 1989
Page 20