Service manual

Section 7 Refrigeration System
Part No. 80-1206-3 7-13
Safety Limit #1
Control Board with Black Microprocessor - Freeze Time exceeds 60 minutes for 3 consecutive freeze cycles
or
Control Board with Orange Label on Microprocessor - Freeze time exceeds 60 minutes for 6 consecutive freeze
cycles.
SAFETY LIMIT NOTES
• Because there are many possible external problems,
do not limit your diagnosis to only the items listed in
this chart.
• A continuous run of 100 harvests automatically
erases the safety limit code.
• The control board will store and indicate only one
safety limit – the last one exceeded.
• If the toggle switch is moved to the OFF position and
then back to the ICE position prior to reaching the
100-harvest point, the last safety limit exceeded will
be indicated.
• If the harvest light did not flash prior to the ice
machine restarting, then the ice machine did not stop
because it exceeded a safety limit.
Possible Cause Check/Correct
Improper installation See “Installation/Visual Inspection Checklist”
Water system Low water pressure (20 psi min.)
High water pressure (80 psi max.)
High water temperature (90°F/32.2°C max.)
Clogged water distribution tube
Dirty/defective water fill valve
Dirty/defective float valve (SU1000C/Q1400C only)
Dirty/defective water dump valve
Defective water pump
Loss of water from sump area
Electrical system Ice thickness probe out of adjustment
Harvest cycle not initiated electrically
Contactor not energizing
Compressor electrically non-operational
Restricted condenser air flow
High inlet air temperature (130°F/54.4°C max.)
Condenser discharge air re-circulation
Dirty condenser fins
Defective fan motor
Low water pressure (20 psig min.)
High water temperature (90°F/32.2°C max)
Dirty condenser
High pressure control defective
Refrigeration system Non-Manitowoc components
Low refrigerant charge
Defective head pressure control
Defective cool vapor valve
Defective compressor
TXV flooding (check bulb mounting)
TXV starving
Non-condensables in refrigeration system
Plugged or restricted high side refrigerant lines or component