Manitowoc S0850M, Service Manual

Page: 60 / 100

Electrical System Section 6
6-22
Part Number 80-1558-3
DIAGNOSING ICE THICKNESS CONTROL CIRCUITRY
Ice Machine Does Not Cycle Into Harvest When Water Contacts The Ice Thickness Control Probe
Step 1 Bypass the freeze time lock-in feature by moving the ICE/OFF/CLEAN switch to OFF and back to ICE.
Step 2 Wait until the water starts to flow over the evaporator (freeze cycle).
Step 3 Disconnect the ice thickness control from the control board, then connect a jumper wire from the control
board to any cabinet ground and monitor the harvest light.
Ice Machine Cycles Into Harvest Before Water Contact With The Ice Thickness Probe
Step 1 Disconnect the ice thickness probe from the control board.
Step 2 Wait until water starts to flow over the evaporator, then monitor the harvest light:
Monitoring of Harvest Light Correction
The harvest light comes on, and 10 seconds later, ice machine
cycles from freeze to harvest. The ice thickness probe is causing the malfunction.
The harvest light comes on but the ice machine stays in the
freeze sequence. The control circuitry is functioning properly. The ice machine is
in a six-minute freeze time lock-in (verify step 1 of this
procedure was followed correctly).
The harvest light does not come on. The control board is causing the malfunction.
Monitoring of Harvest Light Correction
The harvest light stays off and the ice machine remains in the
freeze sequence. The ice thickness probe is causing the malfunction.
Verify that the Ice Thickness probe is adjusted correctly.
The harvest light comes on, and 10 seconds later, the ice
machine cycles from freeze to harvest. The control board is causing the malfunction.
ICE THICKNESS
PROBE CONNECTION
HARVEST LIGHT