Improving Your Air Conditioner

2 HVAC Problems That Can Occur Due to a Faulty Expansion Valve

A central air conditioner runs due to chemical refrigerant that moves through the outdoor condensing unit and then through supply lines into the air handler within your home. There the refrigerant finishes the cooling process in the evaporator coils. An expansion valve guards the point where the supply lines feed into the coils and performs vital functions and protections without which air conditioning systems can suffer serious problems.

What are some of the HVAC problems that can occur due to a faulty expansion valve?

Evaporator Coils Fail Phase Change

Evaporator coils take in liquid refrigerant and perform a carefully calibrated phase change to make the liquid into a gas. The phase change cools off the coils, which in turn cool of the recirculating air going out into your house, and makes it possible for the refrigerant to continue back outside to the condensing unit to start the whole cooling process again. The expansion valve plays an important role in ensuring the coils receive the right amount of refrigerant at a time so that the phase change can happen properly.

If the valve breaks or becomes stuck open or closed, the evaporator coils won't receive the needed amount of liquid refrigerant. The phase change might still happen, but won't happen as efficiently and that efficiency will worsen with each additional passing of the refrigerant. Your unit will start to slow down its cooling abilities and eventually won't blow out any cool air at all.

You will need to call in an HVAC repair service to check to make sure the valve is the problem and not something wrong with the coils. Dirty or broken evaporator coils can also cause a loss of efficiency, and also a potential loss of refrigerant, so it is important to have a professional diagnose and fix the problem.

Compressor Damage or Failure

The compressor inside your condensing unit is the starting point for the cooling process. The part compresses the gas refrigerant so that it can pass into the nearby condenser coils for its phase change into a liquid. How could a part at the beginning of the cooling process become damaged due to a failed expansion valve?

If the valve gets stuck closed, the liquid refrigerant can't move into the evaporator coils. The liquid won't just sit in place inside the supply lines; the refrigerant will start to slide backwards through the coils, which aren't equipped to do anything about a liquid, and then pass on back to the compressor. The compressor also can't do anything with a liquid and its presence can damage or break this vital part of your air conditioner. You would then need to get a new compressor.

To learn more about these issues and how to fix them, contact services like C & D Cooling & Heating Co.