August 9, 2019

It doesn’t have to be winter for ice to form an air conditioner. If you find ice encrusting part of your air conditioner on a hot day, the problem is not weather-related: it’s most likely a problem having to do with airflow or refrigerant.

Below, we’ll go into more detail about why ice forms on air conditioners and what you should do if this happens to you.

Why Ice Forms on Air Conditioners

Refrigerant Issues

Your air conditioner needs a certain amount of refrigerant to properly maintain the cooling process. If your air conditioner’s refrigerant level is too low, ice may begin to form on the AC unit. Sometimes this problem occurs due to a refrigerant leak, but it can also occur if the refrigerant was not charged properly during the installation of your air conditioner.

If ice is forming specifically around your air conditioner’s refrigerant line, it’s best to shut your system off and contact a technician. For safety and environmental reasons, refrigerant issues should only be handled by those who have been professionally trained and certified.

Airflow Issues

Insufficient airflow can cause a number of problems for your air conditioning system. When there isn’t enough warm air flowing through your system, the evaporator coil will reach freezing temperatures. The moisture in the air surrounding the evaporator coil will freeze and accumulate on the coil, resulting in a buildup of ice.

A lack of airflow is usually the result of a clogged air filter. However, this issue can also be caused by closed supply vents, dirty evaporator coils, a bad indoor blower, damaged ductwork, or insufficient ductwork.

What to Do

If you spot ice forming on your air conditioning unit, follow these steps immediately:

      1. Switch your thermostat from “cool” to “off,” but switch the fan setting “on.” Let your system run this way for about 3 hours. This will allow warm air to enter your AC system without your system attempting to cool it, which will help thawing happen faster. While you wait…
      2. Check to see if a clogged air filter is the issue. If the filter is dirty, replace it or clean it, depending on the type of filter your system uses.
      3. Go through your home to make sure all of your supply vents (the vents that air flows out of) are open. Attempting to control the temperature in different rooms by closing vents will reduce the airflow over your AC’s evaporator coil, which is never a good thing.
      4. Make sure that nothing is blocking any of the return vents in your home. This includes furniture, curtains, and anything else that might keep air from flowing freely into those vents from your home.
      5. After running the fan to thaw the ice, see if the problem is fixed when the thermostat is set back to “cool.” If the problem persists, turn your system off and contact an HVAC technician.

It may be tempting, but do NOT try to chisel or scrape the ice off of your unit. This won’t solve the root cause of the problem, and you might damage your equipment in the process.

Woodward Heating Air Plumbing offers a full range of air conditioning repairs as well as 24/7 emergency service so that you can get the relief you need. Contact us today at (503) 749-7760.

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