Gas-Charged TEV (MOP)

Probable cause: Remedy:
Gas-charged TEV loses control.The contents of these charges are such that at
some predetermined valve bulb temperature,
the gas in the bulb becomes superheated,
maximizing bulb pressure (opening force).

Since these bulbs are only charged with small
amount of vapor, whenever the remote tubing or power
element gets colder than the bulb, the gas charge within the bulb will completely migrate to these locations and condense.
If this happens, there is nothing left in the remote
bulb to sense temperature at the evaporator, therefore, the
valve closes or “crosses out.”

 Valve head and tubing must be kept warmer than the remote bulb.Heat tape can be used to wrap the power element and tubing.

Insulate the complete valve.

Install valve outside the refrigerated space.