Where should the sensor bulb on an external equalized TXV be mounted?

The sensor bulb on an external equalized thermostatic expansion valve (TXV) is typically mounted before the external equalizer connection on the suction line. This positioning allows the bulb to accurately sense the temperature of the refrigerant as it enters the evaporator. By placing the sensor bulb in this location, it effectively monitors the pressure and ensures that the TXV can regulate the flow of refrigerant based on the load conditions in the evaporator.

When the bulb senses a change in temperature, it responds by adjusting the TXV's valve position, which helps to maintain optimal refrigerant flow and prevent issues such as evaporator freeze-up or insufficient cooling. The accurate sensing of the refrigerant's conditions before it enters the evaporator is crucial for the system's efficiency and reliability.

While other options may suggest alternative placements, they do not provide the same level of control or responsiveness needed for the TXV to function properly. Mounting the sensor bulb too far from the evaporator or on different lines can lead to inaccurate readings and poor system performance. Therefore, the sensor bulb's correct placement ensures that the refrigeration system operates efficiently and effectively.