Service manual

Section 7Refrigeration System
7-14
Safety Limit #1
Freeze time exceeds 60 minutes for 3 consecutive freeze cycles.
Possible Cause Check/Correct
Improper installation • See “Installation/Visual Inspection Checklist” on page 7-10
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 float valve
• Dirty/defective water dump valve
• Defective water pump
Electrical system • Ice thickness probe out of adjustment
• Harvest cycle not initiated electrically
• Contactor not energizing
• Compressor electrically non-operational
Restricted condenser
air flow (air-cooled models)
• High inlet air temperature (110°F/43.3°C max.)
• Condenser discharge air recirculation
• Dirty condenser filter
• Dirty condenser fins
• Defective fan cycling control
• Defective fan motor
Restricted condenser water
flow (water-cooled models)
• Low water pressure (20 psi min.)
• High water temperature (90°F/32.2°C max.)
• Dirty condenser
• Dirty/defective water regulating valve
• Water regulating valve out of adjustment
Refrigeration system • Non-Manitowoc components
• Improper refrigerant charge
• Defective head pressure control (remotes)
• Defective hot gas valve
• Defective compressor
• TXV starving or flooding (check bulb mounting)
• Non-condensibles in refrigeration system
• Plugged or restricted high side refrigerant lines or component
NOTE: Because there are many possible external
problems, do not limit your diagnosis to only the
items listed in this chart.
NOTE: This chart reflects the removal of safety limits
#3 and #4 from new style control boards.
Safety Limit Notes
• A continuos 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 on position prior to reaching the
100-harvest point, the last safety 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.