Do You Know How Important a Thermostatic Expansion Valve Is?

For such a critical component, the thermostatic expansion valve in your air conditioner doesn’t get as much attention as other parts of your HVAC system. Also abbreviated as “TXV,” this valve plays a vital role in efficient, effective cooling by metering the flow of refrigerant through the system based on the ever-changing cooling demands of your house.

Here’s how the thermostatic expansion valve fits into the circular cooling cycle of a typical air conditioner: After extracting heat from the system airflow at the indoor evaporator coil, AC refrigerant flows to the outdoor condenser coil and disperses that heat into the air. Now a warm liquid as it circles back to the evaporator coil, the refrigerant enters the passages of the TXV, where a needle valve meters the flow of refrigerant released into the evaporator based on present cooling-load requirements. As the refrigerant expands rapidly inside the evaporator coil, it converts into a chilled vapor again, extracting more heat from the indoor airflow as the cooling cycle repeats.

What Can Go Wrong and What to Do If It Does?

A thermostatic expansion valve contains moving mechanical parts and thus may be vulnerable to wear and tear over time. Potential problems include a stuck needle valve, dirt or other debris in the refrigerant flow clogging TXV passages or needle valve, and a malfunctioning temperature-sensing bulb.

Issues with the thermostatic expansion valve can trigger system problems such as:

  • The air conditioner blowing warm air
  • Erratic temperature control
  • Ice formation on the evaporator coil
  • Compressor damage
  • Increased monthly cooling bills

Diagnosing and replacing a defective thermostatic expansion valve is not a DIY project for the average homeowner. Contact the professionals at Paitson Bros. and ask that a qualified technician restore your air conditioner to maximum efficiency and cooling performance. Since 1922, we’ve been the Wabash Valley’s choice for reliable HVAC sales and service.

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    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.

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    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.

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