Test Procedure - Harvest Assist - Scotsman Prodigy Elite MC0322 Service Manual

MC0322 through MC2148
Air, Water, and Remote Cooled Service Manual

Test Procedure - Harvest Assist

1. Test using the controller's indicator lights. Push and release the Harvest button. The Hot Gas indicator light
will be on. At the same time the Harvest Assist Solenoid or Motor will be powered. If the ice on the evaporator
is thin, the ejection pin will extend. If the ice is nearly full sized, the pin will press against the ice until it releases
from the evaporator, then the pin will extend. If the pin extends, the solenoid or motor is good. If not, do a
voltage check.
Unplug the high voltage harness from the harvest assist solenoid. Attach a voltmeter to the harness connector.
Push and release the Harvest button. There should be full voltage at the connector.
If there is and the solenoid does not extend, replace the solenoid. If full voltage is not present, check voltage
at the controller. If there is no voltage, check voltage from the controller to ground. The hot gas / harvest assist
pin is 5.
If there is voltage from that pin to ground, but low voltage at the solenoid harness connection, the harness has
a broken wire or poor connection and must be replaced. If the voltage to ground is low, the controller should be
replaced.
Note: The coil of this valve is internally rectified, will normally show infinite resistance when tested
with an ohmmeter.
Hot Gas or Vapor Valve
1. Test using the controller's indicator lights. If the unit is running, or has been off for more than 4 minutes, push
and release the Harvest button. The Hot Gas indicator light will be on and the hot gas valve will be energized.
The compressor will force discharge gas into the evaporator inlet, warming it.
If the evaporator inlet does not warm up, do a voltage check. Shut the unit off by holding the Off button in
for 3 seconds. Unplug the high voltage harness from the hot gas solenoid. Attach a voltmeter to the harness
connector. Wait 4 minutes.
Push and release the Harvest button. There should be full voltage at the connector. If there is and the solenoid
does not open, replace the solenoid coil. If full voltage is not present, check voltage at the controller. If there
is no voltage, check voltage from the controller to ground or on 220 volt models to the other power leg. The
hot gas pin is 5. If there is voltage from that pin to ground, but low voltage at the solenoid harness connection,
the harness has a broken wire or poor connection and must be replaced. If the voltage to ground is low, the
controller should be replaced.
2. Test with an ohmmeter. Disconnect electrical power. Unplug high voltage harness from hot gas or vapor
valve. Measure resistance of hot gas or vapor valve coil. If open, replace the coil.
This light will be ON during harvest. Both the Hot Gas Valve coil and the
Harvest Assist will have power when this light is ON.
January 2022
Page 58