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Three Signs Your Air Conditioner's Expansion Valve Is Going Bad

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Air conditioners malfunction for many reasons. While the compressor or the condenser it typically the source of the problem, sometimes the issue is a failing expansion valve. Here's more information about what this part does in your A/C unit and how to tell whether it's the reason your appliance isn't working right.

How Expansion Valves Work

Although cold air immediately starts flowing from the air conditioner when you turn it on, the process to get to that point actually involves several complex steps. The air is cooled through the use of a refrigerant. However, that refrigerant is pushed through the tubing and converted from liquid to gas to liquid again in an effort to cool the hot air flowing over the coils.

The expansion valve regulates the amount of refrigerant funneled to the evaporator from the condenser and compressor. This part also depressurizes the refrigerant until it becomes cold enough to cool down the warm air passing through.

As you can see, the expansion valve plays a critical role in reducing the temperature in your home to a comfortable level, and the whole system can go haywire if just this one part malfunctions.

Diagnosing Expansion Valve Problems

There are many reasons why an expansion valve may suddenly go bad. Sometimes the parts are just defective. Other times clogging in the system will damage the part. In many cases, the part simply deteriorates due to age.

Regardless of the cause, fixing a broken expansion valve can be challenging and should only be undertaken by a professional. However, before calling your local HVAC repair technician, it's a good idea to first determine if the valve is the source of the problems. Here are three ways you can tell.

Icing on the Coils or Appliance

As noted previously, the expansion valve is responsible for depressurizing the refrigerant to cool it. In many cases when the valve stops working right, the refrigerant either gets too cold and starts freezing everything in its path or the valve won't turn the flow off at the correct time, so the refrigerant simply keeps moving through the system whether it's needed or not.

Thus, frozen coils, frost spewing from the vents, or ice forming on the appliance's exterior all indicate that something is going wrong with the refrigerant and, coupled with other symptoms, indicates the valve isn't doing its job.

The Compressor Doesn't Turn Off

A consequence of an expansion valve that doesn't shut off like it's supposed to is that the refrigerant continues feeding into the compressor. This, in turn, causes the compressor to continue running nonstop to deal with the gas. You can tell this is happening because your air conditioner will run continuously without shutting down between cycles to let the system rest.

Not only can this problem cause your home to get too cold, but the compressor will wear out faster and eventually break down sooner than expected. It can cost up to $1,800 to replace an A/C compressor, whereas replacing the expansion valve only costs up to $440. Thus, fixing the expansion valve as soon as possible will save you a lot of money in the long run.

Your AC Starts Singing the Song of Its People

It's not unusual for air conditioners to make noise when parts malfunction. As such, a broken expansion valve will cause your machine to make squealing, banging, or clanging noises that worsen over time. So, if your air conditioner starts making odd noises suddenly when you turn it on, it's a good idea to have someone take a look at the machine at the first available opportunity.

To schedule an appointment to have your air conditioner looked at, contact a local HVAC professional at a company like TCS Heating & Air Conditioning.