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Why Does Frost Form on AC Coils?

If you’ve ever checked your air conditioner, you may have encountered frost or ice forming on the evaporator coils. Laymen don’t tend to worry about it too much. Since air conditioners are supposed to generate cool air, the presence of frost or ice seems normal. Unfortunately, the truth is much different. Not only does frost on the coils constitute a serious problem, it will only grow worse if you let it.

Why Is It a Problem?

The process of cooling the air is very delicate and can be throw off very easily. Refrigerant enters the coils in liquid form and under a great deal of pressure. There, it shifts back to gaseous form, which pulls heat from the surrounding air. The gaseous refrigerant returns to the start of the cycle to start the process again, which the AC’s fan blows the cool air through the ducts to lower the temperature in your house.

When that process is out of whack, frost or ice will form on the coils, which is problematic in two ways:

  1. It represents lost cooling potential which should be going into your home, forcing the air conditioner to work harder to do its job.
  2. It forms a barrier of insulation between the refrigerant and the air it’s supposed to cool.

Both of those issues force the system to spend more energy on cooling your home, which not only raises your monthly cooling costs, but puts additional strain on the system itself: increasing the risks of a breakdown. Even worse, the trend will accelerate, with more ice forming, which hampers the cooling process further and creates more strain until the entire system will simply shut down.

What Causes It?

A number of different things can cause frost to form on the AC coils, including (but not limited to) the following:

  • Leaking refrigerant, which means less refrigerant entering the coils in the prescribed amount.
  • Problems with the fan or the fan motor, causing cool air to remain in the system when it should be getting blown into your home.
  • A clogged filter or blockage in the ducts, which similarly causes cool air to remain in your system.
  • Excessively cool temperatures. This is of especial concern here in New England in the spring. Never run your air conditioner when the temperature outside is below 65 degrees.
  • Excessive humidity, which can add to the frost levels. Similar problems can occur is there’s an issue with the AC’s drain system, such as a clog in the drain line.
  • Dust or dirt caked on the coils themselves.

It takes proper training and experience to diagnose these issues, which is why you should always call in a professional service to deal with frost on your system. Never try to scrape the frost off. You’ll likely damage the coils – which can be very expensive to replace – and the frost will simply re-form since the core of the problem lies elsewhere.

To fix these issues with your air conditioner here in Winchester, MA call Cooling Unlimited, Inc. today!

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