If the thermal bulb on a TXV comes loose from the mounting at the outlet of the evaporator, what will occur?

When the thermal bulb of a thermostatic expansion valve (TXV) becomes loose from its mounting at the outlet of the evaporator, it will not be able to accurately sense the temperature of the refrigerant gas leaving the evaporator. The thermal bulb is designed to respond to the temperature changes by adjusting the position of the valve to control the flow of refrigerant.

In this situation, if the thermal bulb is not properly mounted, it may interpret the temperature readings incorrectly. As a result, the TXV will likely respond by opening the valve wider than necessary, feeding more refrigerant into the evaporator. This increased flow can flood the evaporator, leading to inefficient cooling and possible liquid refrigerant returning to the compressor, which can cause damage over time.

The implication here is that the proper function of the thermal bulb is crucial for the accurate operation of the TXV. If it is mispositioned, the ability to regulate refrigerant flow effectively is compromised, prompting the valve to open inappropriately. This highlights the importance of the thermal bulb's placement and the overarching significance of accurate sensing in HVAC system performance.