The installation of the thermostatic expansion valve and the proper location of the remote bulb and external equalizer line are fully as important as correct valve selection. The valve should always be installed as near the liquid header as possible. An upright position with the power assembly on top is preferred. Liquid changed valves may installed in either warm or cold locations. If the valve is of the "gas-charge" type, the valve must be located where it will remain at a higher temperature than the remote bulb.
Thermal expansion valves can help the system achieve a higher energy efficiency. Some manufacture's install the valves at the factory level to add higher efficiency. It is important that the valve is protected if it is added in the field because it can be damaged, if the system is not purged with nitrogen or if the sensing bulb is heated. Improper installation can cause issues that cause the system to not operate efficiently.