Manitowoc Ice QM45 Series - Manual (Page 34)

5-4
Before Calling for Service Section 5
Safety Limit #1
Freeze time exceeds 60 minutes for 3 consecutive freeze cycles.
Possible Cause Check/Correct
Improper installation • See “Installation Instructions” Section two of this manual
Water system • Low water pressure (20 psi minimum.)
• High water pressure (80 psi maximum.)
• High water temperature (90°F/32.2°C maximum.)
• Clogged water distribution tube
• Dirty/defective water float valve
• Loss of water from sump area
• Defective water pump
Electrical system • Ice thickness probe out of adjustment
• Harvest cycle not initiated electrically
• Relay not energizing
• Compressor electrically non-operational
Restricted condenser air flow
(air-cooled models)
• High inlet air temperature (110°F/43.3°C maximum.)
• Condenser discharge air recirculation
• Dirty condenser filter
• Dirty condenser fins
• Defective fan cycling control
• Defective fan motor
Refrigeration system • Non-Manitowoc components
• Improper refrigerant charge
• Defective hot gas valve
• Defective compressor
• TXV starving or flooding (check insulation and bulb mounting)
• Non-condensables in refrigeration system
• Plugged or restricted high side refrigerant lines or component
Safety Limit #2
Harvest time exceeds 3.5 minutes for 3 consecutive harvest cycles.
Possible Cause Check/Correct
Improper installation • See “Installation Instructions” Section two of this manual
Water system • Water area (evaporator) dirty
• Water freezing behind evaporator
• Low water pressure (20 psi min.)
• Loss of water from sump area
• Clogged water distribution tube
• Dirty/defective water float valve
• Defective water pump
Electrical system • Ice thickness probe out of adjustment
• Ice thickness probe dirty
• Bin switch defective
• Premature harvest
Refrigeration system • Non-Manitowoc components
• Improper refrigerant charge
• Defective hot gas valve
• TXV flooding (check insulation and bulb mounting)
• Defective fan cycling control
Because there are many possible external problems,
do not limit your diagnosis to only the items listed in these charts.