K90-KPCS-IM-2
18/04/22
- 19 -
System Troubleshooting Guide Continued
Condensing Unit Problem
Possible Causes
Room temperature too high.
1. Defective room thermostat or improper differential / setting.
2. Malfunctioning liquid line solenoid valve.
3. Insufficient air across evaporator coil (iced up coil, product
blocking evaporator, fan blade / motor problem).
4. Improper evaporator superheat (low refrigerant charge,
plugged TXV strainer, poor TXV bulb contact, incorrect
TXV setting).
5. Malfunctioning condensing unit.
Room temperature too low.
1. Defective room thermostat or improper differential / setting.
2. Malfunctioning liquid line solenoid valve.
Ice accumulating on ceiling.
1. Defrost on too long (improper setting / defective termination
thermostat, improper setting / defective time clock).
2. Too many defrosts per day.
3. Fans not delayed after defrost (improper setting / defective
fan delay thermostat).
Evaporator coil not clear of ice after defrost.
1. Defrost on too short (improper setting / defective
termination thermostat, improper setting / defective time clock).
2. Electric heaters defective / miswired / low voltage.
3. Not enough defrosts per day.
4. Air defrost evaporator operating at too low of temperature
(require electric defrost).
5. Defective / miswired interlock at compressor contactor.
6. Defective defrost contactor or coil.
Ice building up in drain pan.
1. Improper slope in pan.
2. Blocked drain line (unheated , not insulated).
3. Electric heater in drain pan defective / miswired / low voltage).
4. Not enough defrosts per day.
5. Lack of or improper P-trap in drain line.
Evaporator fans will not operate.
1. Main power switch open.
2. Fuse blown or tripped circuit breaker.
3. Defective contactor or coil.
4. Room temperature too high (fan delay thermostat open).
5. Fan delay thermostat improper setting / defective.
6. Defective fan motor (low voltage / tripped on thermal overload).
7. Defective time clock.
8. Normal mode during defrost cycle (electric defrost type evaporator).
SYSTEM TROUBLESHOOTING (cont’d)
Before any components are changed on the refrigeration system, the cause of the failure must be identified. Further problems will exist
unless the true cause or problem is identified and corrected.
IMPORTANT TROUBLESHOOTING NOTE
