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Heat Pump Troubleshooting
8. Symptom: Low refrigerant discharge pressure
Possible Causes
Low suction pressure
Incorrect fan control settings
9. Symptom: High refrigerant discharge pressure
Possible Causes
System overcharged with refrigerant (especially at low ambient temperature in
heating mode)
Dirty tube and fin surface
Non-condensables in heating mode
Incorrect fan control settings
Condensing fans not operating in cooling mode
Discharge shut off valve partially closed
EXV does not function properly (especially at low ambient in heating mode)
Overshooting LWT temperature in heating mode
10. Symptom: Low chilled water temperature
Possible Causes
Temperature controllers set too low
Low water flow
Faulty system temperature sensor
11. Symptom: High chilled water temperature
Possible Causes
Load higher than capacity of heat pump
Loss of refrigeration charge
Fouled evaporator
High water flow rate
Faulty system temperature sensor
12. Symptom: Compressor thermal protector switch open
Possible Causes
Operating beyond design conditions
Discharge valve partially shut
Faulty compressor overload
60
Potential Solutions
See low refrigeration suction pressure
Check fan settings
Potential Solutions
Remove excess refrigerant
Clean with compressed air or water spray, use fin comb if fins are bent
Purge non-condensables
Check fan functionality and settings
Check fan functionality and settings
Open valve
Check EXV functions; Check SSH settings
Water system volume needs to increase; Check stage band control settings
Potential Solutions
Reset temperature setpoint
Clean strainer; Check pump, VFD, and differential pressure settings; Check to
ensure electric and manual water valves are fully open
Replace temperature sensor
Potential Solutions
Refer to heat pump design specifications
Check refrigerant charge
Reverse flush evaporator; Check strainer for debris
Check pump, VFD and differential pressure settings
Replace temperature sensor
Potential Solutions
Check fan switch or fan pressure settings as appropriate
Open valve
Replace overload if external type provided
ARTC-SVX006A-EN
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