Know What an Expansion Valve Can Do for Your HVAC Unit

The expansion valve is a component of your central AC critical to the process of moving indoor heat outdoors during hot weather. Thermal expansion valves (known by the abbreviation “TXV”) aren’t what you would call high tech, but they are a critical device when it comes to keeping you cool on a hot day.

Expanding and Cooling

In an air conditioner’s cooling cycle, cool liquid refrigerant flowing through the evaporator coil extracts heat from the AC airflow.  As the refrigerant converts into a warm, low-pressure gas, the flow continues to the outdoor unit, where the compressor pressurizes the refrigerant’s heat load, then into the condenser coil where the heat is dispersed into outdoor air.

Because the AC cycle is a circle, the refrigerant flow loops back to the evaporator coil to extract more heat.  The warm gaseous refrigerant must now be converted back to a cool liquid. That’s where the expansion valve comes in.

Warm, pressurized refrigerant vapor forced through the tiny orifice of the TXV rapidly decompresses. As a result, the chemical properties of the refrigerant convert from a vapor back to a cool liquid at a temperature of 40 to 50 degrees, efficiently absorbing heat again.

When Good TXV Goes Bad

Expansion valves are generally reliable and long-lasting. However, the component combines moving parts and very small tolerances and may exhibit symptoms of wear and tear over time. Here are some signs of a TXV that needs replacement.

  • Frost or ice accumulation on the AC evaporator coil.
  • System compressor runs continuously instead of cycling on and off.
  • No cool air. AC blows warm air only.

Replacement of an expansion valve is a straightforward fix for an experienced, certified HVAC technician. While certain repairs to an existing valve might be possible, replacing the existing TXV with a new component is generally the most practical option in terms of cost to the homeowner as it relates to service-life expectancy.

If you suspect expansion valve problems, contact the professionals at Paitson Bros. We’re in our 100th year of reliable sales and service to the Terre Haute community.

This entry was posted in HVAC System and tagged . Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.

Post a Comment

Your email is never published nor shared.

You may use these HTML tags and attributes <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

What is 0 + 0 ?
Please leave these two fields as-is:
  • Click Here, For
  • » Call Us: 1 (812) 232-2347

  • How Can We Help?

    We're glad to answer questions... just click below for our contact form:

    Free Estimate

    Schedule Service

  • Recent Posts

  • Topics

  • Life's Journey &quo...
    By Jeff Paitson
  • About Jeff

    Jeff Paitson Jeff Paitson is a third generation business owner who continues to run the business with the same values that have been passed down from previous generations since 1922.

    Jeff’s belief is that the business belongs to Jesus Christ; therefore 10 percent of the company’s profits go toward the Maryland Community Church.

    Jeff is a Terre Haute Chamber of Commerce member and in his spare time, he enjoys photography.
    More »
  • About Ethan

    Ethan Ethan Rayburn is a lifelong resident of Terre Haute and a 2005 graduate of Purdue University.

    An Eagle Scout, Ethan spent four years as a non-profit executive with the Boy Scouts of America before joining Paitson Bros. as a comfort advisor and later General Manager. In that role, Ethan has brought a renewed enthusiasm for customer care, integrity, value, and service to Paitson Bros. Heating & Air Conditioning.

    Ethan enjoys singing and was a member of the Purdue Varsity Glee Club. He also enjoys playing and coaching soccer, spending time with his family and two young boys, and volunteering his time and resources with his church, Terre Haute First Baptist Church, which he has attended from a very young age.
    More »