Heatcraft Refrigeration Products 25001501 - Manual (Page 21)

BEACON CONTROLLER
21
SERVICE DIAGNOSIS CHART - GENERAL
PROBLEM POSSIBLE CAUSE POSSIBLE CORRECTIVE ACTION
Low suction pressure 1. Insufficient refrigerant 1. Check system for leaks; repair leaks &
add refrigerant
2. Freezer coil iced up 2. Check defrost system operation &
correct fault condition
3. Plugged liquid line filter drier 3. Replace filter drier
4. Plugged suction filter 4. Replace suction filter
5. Expansion valve starving coil 5. Check expansion valve superheat setting on
control board; check expansion valve screen
Loss of oil or loss of oil 1. Insufficient oil in the system 1. Add oil until sight-glass is 1/2 full
pressure 2. Compressor short cycling 2. Check low pressure control settings
3. Excessive liquid refrigerant in 3. Check crankcase heater; check expansion valve
compressor crankcase superheat setting on control board; check for
internal rupture of heat exchanger
4. Worn bearings 4. Replace compressor
Freezer coil icing 1. Insufficient refrigerant 1. Check system for leaks; repair leaks &
add refrigerant.
2. Wrong defrost end temp setting 2. Check unit cooler instructions. Raise setting.
3. Wrong defrost fail-safe setting 3. Check unit cooler instructions. Raise setting.
4. Not enough defrost for application 4. Check for subcooled liquid, incorrect nozzle
5. Coil not feeding properly selection, insulate liquid line, restricted coil
6. System undersized 5. Do heat load & check sizing