Manitowoc S Service Manual page 120

Refrigeration System
Safety Limit #1
Refer to previous page for safety limit operation.
Freeze time exceeds 60 minutes for 6 consecutive freeze cycles.
Possible Cause
Improper installation
Water system
Electrical system
Miscellaneous
Refrigeration system
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.
7-14
Check/Correct
See "Installation/Visual Inspection Checklist"
Low water pressure [20 psi (138 kPa) min.]
High water pressure [80 psi (552 kPa) max.]
High water temperature (90°F/32.2°C max.)
Clogged water distribution tube
Dirty/defective water fill valve
Dirty/defective water dump valve
Defective water pump
Loss of water from sump area
Low incoming voltage
Ice thickness probe out of adjustment
Harvest cycle not initiated electrically
Contactor not energizing
Compressor electrically non-operational
Defective fan cycling control
Defective fan motor
Restricted condenser airflow
High inlet air temperature (Self-Contained -110°F/43.3°C max.;
Remote - 120°F/49°C max.)
Condenser discharge air recirculation
Dirty condenser filter
Dirty condenser
Restricted condenser water flow
Low water pressure [20 psi (138 kPa) min.]
High water temperature (90°F/32.2°C max.)
Dirty/defective water regulating valve
Water regulating valve out of adjustment
Improper refrigerant charge
Non-Manitowoc components
Defective head pressure control (remotes)
Defective harvest valve
Defective compressor
TXV starving or flooding (check bulb mounting)
Non-condensables in refrigeration system
Plugged or restricted high side refrigerant lines or component
• 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 a Safety Limit light did not flash prior to the ice
machine restarting, then the ice machine did not stop
because it exceeded a safety limit.
Section 7
Part Number 80-1480-3