Thread: What Is It

So what does this thing do? I haven't seen one before.

It's on a Carrier central air conditioning system.

I asked your question and picture over on the HVAC board and got the following:

A thermal expansion valve is a component in an air conditioning system that controls the amount of refrigerant flow into the evaporator thus controlling the superheat at the outlet of the evaporator.

Here is a basic explanation of a TXV for HVAC systems.

Dom.

Thanks. That's definitely it.

You will see a TXV on (usually) systems of higher capacity OR ones that have had problems with frosting the coil. As I recall the newer systems with R410a refrigerant don't get as cold and the frosting issue is less of a concern.

TEV. Like others said, higher efficiency units will have. Next step up from cap tube.