Service manual

Section 7 Refrigeration System
7-15
Safety Limit #2
Harvest time exceeds 3.5 minutes for 3 consecutive harvest cycles.
Possible Cause Check/Correct
Improper installation • See “Installation/Visual Inspection Checklist” on page 7-10
Water system • 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
Electrical system • Ice thickness probe out of adjustment
• Ice thickness probe dirty
• Bin switch defective
• Premature harvest
Refrigeration system • 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
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.