Manitowoc J250 Service Manual page 120

Section 7
Safety Limit #2
Harvest time exceeds 3.5 minutes for 3 consecutive harvest cycles.
Possible Cause
Improper installation
Water system
Electrical system
Refrigeration system
NOTE: Because there are many possible external
problems, do not limit your diagnosis to only the
items listed in this chart.
• See "Installation/Visual Inspection Checklist" on page 7-10
• Water area (evaporator) dirty
• Dirty/defective water dump valve
• Vent tube not installed on water outlet drain
• Water freezing behind evaporator
• Plastic extrusions and gaskets not securely mounted to the evaporator
• Low water pressure (20 psi min.)
• Loss of water from sump area
• Clogged water distribution tube
•
Dirty/defective float valve
• Defective water pump
• Ice thickness probe out of adjustment
• Ice thickness probe dirty
• Bin switch defective
• Premature harvest
• Non-Manitowoc components
• Water regulating valve dirty/defective
• Improper refrigerant charge
• Defective head pressure control valve (remotes)
• Defective harvest pressure control (HPR) valve (remotes)
• Defective hot gas valve
• TXV flooding (check bulb mounting)
• Defective fan cycling control
Refrigeration System
Check/Correct
NOTE: This chart reflects the removal of safety limits
#3 and #4 from new style control boards.
7-15