What indicates a properly functioning TXV?

A properly functioning Thermostatic Expansion Valve (TXV) is indicated by superheat remaining constant under varying load conditions. The TXV's primary function is to regulate the flow of refrigerant into the evaporator coil based on the needs of the system, effectively maintaining the correct superheat level.

When the system experiences a change in load, the TXV adjusts the refrigerant flow to ensure that the superheat stays steady. This constancy indicates that the TXV is successfully responding to changes in evaporator conditions and helping to ensure that the evaporator is neither starved of refrigerant nor flooded. Thus, the balance it maintains is critical for the efficient operation of refrigeration systems.

Conversely, if superheat is consistently high, it might suggest that the TXV is allowing insufficient refrigerant into the evaporator, which is not ideal for optimal performance. Fluctuations in subcooling can indicate issues with the condenser or other components, while a quiet compressor does not provide a definitive measure of the TXV's operational state. Therefore, the stability of superheat under load is the best indicator of proper TXV function.