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SYMPTOM / FAULT
Compressor stopped because
of high head pressure
"HIGH REFRIG PRESS"
Compressor stopped because
low suction pressure
"LOW REFRIG PRESS"
Compressor stopped because
of low oil pressure
"OIL PRESSURE"
Compressor stopped because
SSMP open
"SSMP"
Compressor stopped because
motor starter protector open
"MTR STARTER"
High air temperature leaving
the evaporator
"HIGH EVAP AIR TEMP"
Compressor will not start
Compressor cycles
intermittently
18
TROUBLE SHOOTING GUIDE
POSSIBLE CAUSES
1. Faulty high pressure transducer
2. Refrigerant overcharge
3. Air in refrigeration system
4. Water-cooled units
A. Insufficient water flow thru condenser
(1) Water regulating valve not adjusted
(2) Dirty water strainer
(3) Water lines too small
(4) Discharge shutoff valve not fully open
(5) Condenser water pump off
(6) Plugged or scaled condenser tubes
B. Inlet water temperature too high
5. Air-cooled units
a) Condenser dirty
b) Fans not operating
1. Low refrigerant charge
2. Excessive superheat
1. Low oil charge
2. Clogged oil suction strainer
3. Clogged oil line
4. Worn oil pump
5. Worn compressor bearings
1. Low voltage
2. Line imbalance
3. Excessive return gas temperature
1. Low voltage
2. Line imbalance
3. Compressor motor drawing excess current
1. Unit overload
2. Insufficient cooling
1. Power off
2. Thermal overload switch open
3. Oil safety switch
4. Dirty contacts
5. Loose electrical connections or faulty
wiring
6. Compressor motor burned out
7. Solenoid valve closed
1. Faulty low pressure transducers
2. Low refrigerant charge
3. Suction valve closed or throttled
4. Hot gas by-pass valve sticking
CORRECTIVE ACTION
Check pressure reading.
Reclaim excess refrigerant.
Check for leaks and recharge unit.
Properly dispose of old refrigerant.
Adjust water regulating valve.
Clean water strainer.
Increase water main size to condenser.
Open valve.
Check and start.
Clean tubes.
Use colder water.
Clean condenser.
Check for power; if fan motor faulty
repair or replace.
Check for leaks and repair, then add
refrigerant.
Reset expansion valve and/or adjust
hot gas by-pass valve.
Add oil.
Clean.
Remove obstruction.
Replace pump assembly.
Replace compressor.
Check power supply.
Check power supply.
Check liquid injection valve and
refrigerant charge.
Check power supply.
Check power supply.
Check motor winding resistance.
Check inlet flow, pressure and
temperature and verify if within
design conditions.
Check refrigeration system for
faults.
Check main switch, fuses and wiring.
Reset. (Allow time to reset)
Reset.
Clean all control contacts.
Tighten connections. Check wiring
and rewire.
Check and replace, if defective.
Check for burned out holding coil
Replace if defective.
Check pressure readings.
Repair leaks and add refrigerant.
Open valve.
Repair.
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