Service Diagnosis - Scotsman NW507 Service Manual

SERVICE DIAGNOSIS

The table below is intended as a quick
reference to aid the Service Agent in
determining the cause of a particular type of
malfunction, as well as the recommended
repair. It is not intended to be an exclusive list.
SYMPTOM
Warning Red LED ON
No warning LED/LIGHT ON
Bin full Yellow LED ON
Machine runs, compressor
does not.
Machine runs, makes ice,
does not try to harvest.
Machine runs, makes and
harvests ice but very slowly.
Low ice capacity.
Machine makes irregular ice.
Reference to other portions of this manual,
including wiring diagrams, installation, and
operation
determine the cause of a problem.
POSSIBLE CAUSE
See page 23-24
P.C. Board inoperative.
No power to unit.
Bin Full of ice.
P.C. Board compressor
relay open.
Compressor contactor
open.
Compressor relay open.
Compressor winding open.
Ice thickness control open.
Too soft water.
Built-in relay on
P.C. Board open.
Low refrigerant charge.
High discharge pressure
due to not-condensable or
overcharge.
Inefficient compressor.
Condenser dirty.
Low water flow
(Water-cooled).
High air temperature
(air-cooled).
Plugged water distributor.
TXV superheat wrong.
Refrigerant charge low.
37
are recommended
CORRECTION
See page 23-24
Remove board and check.
Check electrical source.
None.
Test and replace.
Test and replace.
Test and replace.
Test and replace.
Check sensor fingers if are not
covered with scale sediment.
Water electrical conductivity must be
higher then 20 μs. Machine can't
run with demineralized water.
Check and replace P.C. Board.
Check system for correct refrigerant.
charge. Check for leak weight in
charge.
Evacuate and weigh in charge.
Replace.
Clean.
Check and repair.
Check temperature of air entering
condenser.
Clean water distributor.
Adjust or replace.
Adjust-check for leak.
Recharge.
Page 30
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