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Low head pressure, starved evaporator, high superheat and high subcooling readings, short cycling, poor cooling in winter
What is going on
Possible causes and checks for: low head pressure, starved evaporator, high superheat and high subcooling readings, short cycling, poor cooling in winter.
Likely causes
- No/failed head pressure control: louver bellows or linkage stuck
- Fan cycling switch failed
- Fan speed control thermistor bad
- Receiver heater out, ORI/ORD/LAC valve stuck or wrong setting
- Receiver too small to flood condenser
- Insufficient charge for winter flooding
- Split condenser valve not shifting
- Strong cold wind
Check in this order
- Head pressure vs ambient
- Louver movement
- Fan operation vs pressure, ORI setting and ORD ~20 psi differential
- Charge/receiver level (sight glass)
- Split valve position and bleeder line
- Check valves
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