How the TXV Works
The thermostatic expansion valve (TXV) regulates refrigerant flow into the evaporator based on superheat. It maintains optimal evaporator performance across varying load conditions.
Symptoms of TXV Problems
- Low superheat (flooding back to compressor)
- High superheat (starving evaporator)
- Inconsistent temperatures
- Icing on suction line
- Compressor overheating
Common Causes
- Stuck valve (open or closed)
- Lost bulb charge
- Improper bulb mounting
- Contamination or debris
Diagnostic Steps
- Measure superheat at evaporator outlet
- Check bulb mounting and insulation
- Verify proper subcooling at valve inlet
- Inspect for moisture or contamination