Clark Heating and Cooling blog

Clark Heat and Cool is a Phoenix, Arizona based HVAC specialty service company and this blog is to help keep their client, and prospective clients, up to date with changes in the HVAC industry.

Thermostatic Expansion Valve (TXV)

Thermostatic Extension Valve | 22 Point Inspection | Clark Heating & Cooling 
This twisty part which is found in an A/C unit regulates the refrigerant flow for the indoor coil.  It is called a thermostatic expansion valve, or TXV, for short.  The TXV makes sure the A/C unit maintains maximum efficiency by allowing only a certain amount of refrigerant to flow into the evaporator. This control over the flow of refrigerant is necessary to make the evaporator as efficient as possible. It also prevents refrigerant from flowing back into the compressor. There's a pretty good video on YouTube that shows you how it works. 

Thermostatic Extension Valve | 22 Point Inspection | Clark Heating & Cooling

What the Thermostatic Expansion Valve Doesn't Control

Controlling the flow of refrigerant is the function of the TXV. It doesn't control any of the following:

1. Air Temperature

2. Head Pressure Capacity

3. Suction Pressure

4. Humidity

What Makes the TXV Fail

This part usually holds up pretty well. When it does fail, it's usually in the middle of summer, when the extremely high outdoor temperatures just cause everything to malfunction and break down.  There are a few ways to keep the TXV running for as long as possible. However, there are a few things that will make the thermostatic expansion valve fail:
151. Under sized return duct work,

2. Improper refrigerant charge

3. Improper factory installation

It is very important to have the air conditioner installer inspect the TXV carefully to make sure the duct work is the proper size and that the refrigerant charge is accurate according to the manufacture’s specifications.

The TXV is one of the more pricey parts to replace on your air conditioner, so you'll want to make sure the above items are taken care of as necessary.  Clark Heating & Cooling will gladly check these for you!  Call us today!

Stay Informed

When you subscribe to the blog, we will send you an e-mail when there are new updates on the site so you wouldn't miss them.

Happy Labor Day!
Run Capacitor: Not Quite The Flux Capacitor

Related Posts

What our clients are saying

We just had them come out to install a new AC unit on our house. Not only are they efficient and on time but they did a fantastic job and are super...
Katie Sjoblom Wynn
I called RKS at 7am when they opened. No answer, I left a message. I caled Clark at about 8:30am..they said they would come out around...
Louis C.
My air condition problem was over Labor Day weekend. Ivan brought out a room air condition at 7PM or on Sunday night and set it up, which was a...
Patty O’Neal
When it came time to build my agency's office there was only one Phoenix based HVAC team I trusted, Clark Heat and Cool. I'll always support local,...
Bill Backus