Where is the sensing bulb for a TXV typically mounted?

The sensing bulb for a thermostatic expansion valve (TXV) is typically mounted on the discharge line of the evaporator. This location is crucial because the sensing bulb measures the temperature of the refrigerant leaving the evaporator. By monitoring this temperature, the TXV can accurately control the flow of refrigerant into the evaporator based on the cooling demand.

When the refrigerant temperature at the bulb indicates that more cooling is needed (i.e., the temperature increases), the TXV opens further to allow more refrigerant to flow into the evaporator, thus enhancing cooling. Conversely, if the temperature drops, the valve closes to reduce refrigerant flow, preventing excessive cooling and ensuring efficient operation.

If the sensing bulb were located on the discharge line of the compressor or the suction line of the condenser, it would not provide the same level of performance or responsiveness related to the cooling load, as those points do not directly reflect the temperature changes in the cooling process occurring in the evaporator. The position of the sensing bulb is critical in providing the accurate feedback necessary for the TXV to maintain the desired temperature and efficiency of the refrigeration system.