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13. Symptom: No low voltage (24 Vac)
Possible Causes
Transformer primary side fuse open
Transformer defective
No primary voltage on transformer
14. Symptom: Thermal Expansion valve superheat too high
Possible Causes
Water/glycol temperature too warm
Obstructed filter dryer
Low refrigerant charge
Improper and not enough heat transfer at air coil
Sensing bulb not properly located
Defective or improper settings of EXV/TXV
15. Symptom: Thermal expansion valve superheat too low
Possible Causes
Sensing bulb not properly located
Defective thermostatic element (TXV is cooling mode)
EXV/TXV valve superheat setting is too low or not functioning properly
16. Symptom: Contactor/relay inoperative
Possible Causes
Coil shorted or open
Mechanical parts broken or jammed
Contacts pitted or burned
No 24 Vac to coil
17. Symptom: Freeze protection safety activated
Possible Causes
Chiller setpoint is too low
Low water flow
Low suction pressure
ARTC-SVX006A-EN
Heat Pump Troubleshooting
Potential Solutions
Check fuse prong contact points; Replace fuse
Replace transformer
Check breakers, fuses; Check power supply specifications
Potential Solutions
Check setpoints; Check charge
Replace dryer core
Recharge refrigerant as per data plate
Check tube and fin surface; Check fan settings
Check if secured to pipe or insulated; Check sensor position on pipe
Check EXV/TXV functions; Check EXV/TXV settings
Potential Solutions
Check if secured to pipe or insulated; Check sensor position on pipe
Replace power head
Check EXV/TXV settings and functionality
Potential Solutions
Replace coil
Replace assembly
Replace contactors
Replace secondary fuse to transformer; Check transformer
Potential Solutions
Use a proper setpoint
Clean strainer; Check pump, VFD and differential pressure settings
See "low suction pressure"
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