Manitowoc S0850M, Service Manual

Page: 76 / 100

. Refrigeration System Section 7
7-10
Part Number 80-1558-3
Safety Limit #2
Refer to page 7-8 for safety limit operation.
Harvest time exceeds 3.5 minutes for 500 consecutive harvest cycles.
SAFETY LIMIT NOTES
• Because there are many possible external problems,
do not limit your diagnosis to only the items listed in
this chart.
• A continuous 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 ICE position prior to reaching the
100-harvest point, the last safety limit exceeded will
be indicated.
• If a Safety Limit light did not flash prior to the ice
machine restarting, then the ice machine did not stop
because it exceeded a safety limit.
Possible Cause Check/Correct
Improper installation See “Installation/Visual Inspection Checklist”
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 (138 kPa) min.]
Loss of water from sump area
Clogged water distribution tube
Dirty/defective water fill 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 harvest valve
TXV flooding (check bulb mounting)
Defective fan cycling control