Trane Arctic Thermafit AXM, Installation, Operation And Maintenance Manual

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