Acson international A5WCP0060A-FP, Installation Operation & Maintenance

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Issue: O-WCP15-SEP21-2 Page 52
9.0 TROUBLE SHOOTING
PROBLEM POSSIBLE CAUSE ACTION
LACK OF
COOLING
EFECT
1. Faulty compressor or lack of
compression. 1. Check discharge pressure for
compression. Inspect compressor and
replace if necessary.
2. Temperature of air entering evaporator
too high. 2. Reduce load to design KW value.
3. Fouled condenser and/or evaporator tube
surface. 3. Inspect surface and clean.
4. Low refrigerant charge. 4. Repair refrigerant leak, add refrigerant.
5. Thermal expansion valve out of
adjustment or erratic. 5. Adjust superheat or replace power
element.
6. Improper air flow through evaporator. 6. Determine flow and adjust correctly belt
tension.
7. Room thermostat not operating properly. 7. Inspect thermostat and replace if
necessary.
TRIPPING OF
COMPRESSOR(S)
A. DUE TO LOW PRESSURE CUT OUT
1. Reduced air flow through evaporator. 1. Inspect surface & clean, check
evaporator fan drive
2 Low refrigerant charge. 2. Repair refrigerant leak, add refrigerant.
3. Broken expansion valve. 3. Replace expansion valve.
4. Restricted refrigerant line. 4. Determine the cause of restriction and
repair.
5. Faulty low pressure cut-out. 5. Replace.
B. DUE TO HIGH PRESSURE CUT-OUT
1. Air in refrigeration system. 1. Re-evacuate refrigeration system and
charge with new refrigerant.
2. Excess refrigerant charge. 2. Bleed off excess refrigerant.
3. Faulty high-pressure cut-out. 5. Replace.
C. DUE TO COMPRESSOR OVERLOAD TRIPPING
1. Compressor over-current, under voltage
or single phasing. 1. Check electrical supply, contactors,
wiring, and rectify fault.
2. Excessive discharge pressure. 2. See section B above.
3. Compressor over-heating due to low
refrigerant. 3. Check refrigerant charge (fix leak), top
up refrigerant if necessary.
4. Compressor motor has a winding
shorted. 4. Replace compressor.
5. Liquid refrigerant in compressor causing
valve plate damage and lack of
compression. 5. Check that crankcase heater is
functioning properly.
6. Defective overload protector. 6. Replace protector.
EXCESSIVE
BELT
"SCREAM"
WHEN FAN(S)
START UP 1. Slipping belts.
1a. Apply belt dressing/belt tensioning.
1b. Adjust belt tension correctly.