Section 7Refrigeration System
7-16
Safety Limit #3
Compressor discharge temperature fell below 85°F/29.4°C for 3 consecutive harvest cycles.
Possible Cause Check/Correct
Improper installation • See “Installation/Visual Inspection Checklist” on page 7-10
Ice thickness probe • Check thickness setting
Water system - insufficient
water flow over evaporator
• Low water pressure (20 psi min.)
• Loss of water from sump area
• Clogged water distribution tube
• Dirty/defective float valve
• Dirty/defective water dump valve
• Defective water pump
Refrigeration system • Non-Manitowoc components
• Defective head pressure control valve (remotes)
• Defective harvest pressure control (HPR) valve (remotes)
• Defective fan cycle control
• Improper refrigerant charge
• Defective hot gas valve
• TXV flooding (check bulb mounting)
Thermistor • Defective thermistor
Safety Limit #4
Compressor discharge temperature exceeded 255°F/123.8°C for 15 continuous seconds.
Possible Cause Check/Correct
Improper installation • See “Installation/Visual Inspection Checklist” on page 7-10
Restricted condenser
air flow (air-cooled models)
• High inlet air temperature (110°F/43.3°C max.)
• Condenser air recirculation discharge
• 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
• Defective head pressure control valve (remotes)
• Improper refrigerant charge
• Non-condensibles in refrigeration system
• High side refrigerant lines/component restricted or plugged
• TXV starving (check bulb mounting)
• Defective compressor
Thermistor • Defective thermistor
NOTE: Because there are many possible external
problems, do not limit your diagnosis to only the
items listed in these charts.
NOTE: Safety Limits #3 and #4 are not used on later
production J-model ice machines. Any fault that
would stop the ice machine on safety limit #3 or #4
would also stop the ice machine on safety limit #1 or
#2.
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