Central Air Conditioner

22 Jul, 2021

Wondering what to do about a frozen evaporator coil? It can be a huge problem if your air conditioner stops working because of a frozen evaporator coil, especially if it’s in the middle of a hot summer day. With that in mind, we’ve created the guide covering everything you need to know about a partially frozen evaporator coil, ice on an evaporator coil, and more.

What is an Evaporator Coil? (What is its Function?)

The evaporator coil refers to the part of your air conditioner system that absorbs the heat and takes it out of the air circulating around your home. It is typically either located inside of the air handler or attached to the furnace. The evaporator coil works with the condenser coil to finish the heat exchange process that leads to cool air.

The evaporator coil is filled with evaporated refrigerant or Freon, which the compressor pumps as a liquid to the metering device and then the evaporator. The air pushed from the blower fan through the evaporator coil moves over the evaporator coil where the refrigerant or Freon in the evaporator absorbs the heat from the air inside your home.

What Causes an Evaporator Coil to Freeze?

The evaporator coil should be cold yet not freezing in a properly functioning air conditioner system. When working correctly, the evaporator circulates the refrigerant or Freon vapor at a temperature of about 40 degrees. This is the best temperature to take heat from the air moving through the evaporator coil but not freezing enough to create ice within the coil.

What happens when your AC coils are frozen? If you do have any ice in the evaporator coil, this will lead to the creation of more ice, and eventually, the entire evaporator coil will become a huge block of ice. With an evaporator coil freezing, the blower fan will strain to pull air through the evaporator coil and will most likely overheat. Also, your compressor will probably become overstressed as your air conditioner continues to run constantly, working overtime to make up for the frozen coil in the AC unit.

Eventually, your entire air conditioner might shut down, or the circuit breaker might trip. As the block of evaporator coil ice melts at a rapid pace, you will probably run into even more issues with the frozen evaporator coil and defrost. For example, several gallons of water might come out of the air handler, which can either leak through the ceiling or soak and damage important structural parts of your home.

How to Troubleshoot Evaporator Coil Issues

But how exactly do you troubleshoot problems with your evaporator coil, like an AC condenser that’s frozen? Here are the steps we recommend for fixing the frozen evaporator coil:

  • Turn off the air conditioner. First, to reduce any additional damage, you need to turn off the air conditioner at the thermostat. We recommend turning the fan button to fan only in order to blow warm air over the evaporator coil and speed up the melting process. If the accumulation of ice on the evaporator coil goes beyond the condensate drip pan dimensions under the air handler, you should get ready to catch any dripping water and help prevent water damage with containers.
  • Check the air filter. The next step is to check out the air filter. A clogged filter can undoubtedly decrease the level of airflow, and low system airflow is one of the leading causes of an evaporator coil freezing. The refrigerant going through the evaporator can’t extract enough heat when the air conditioner system airflow goes below a certain level. Then the temperature of the refrigerant will drop below 32 degrees, and ice will form on the surface of the freezing evaporator coil as the evaporator coil keeps condensing water.
  • Install a new filter. Next, you need to install a new air filter, especially if the current air filter seems very clogged or dirty. Simply wait for the ice to melt, then you can restart the air conditioner system. If the freezing happens again, you should shut down the whole air conditioner system and contact a professional HVAC service to assist you.
  • Check the blower. You should also check the blower since a malfunctioning blower fan or a very dirty blower can lead to low or no airflow. The motor could be defective, or the blower drive belt could be broken, especially if you don’t feel any airflow when you switch the fan switch to fan only on the thermostat. We recommend getting further advice from a professional HVAC service.

How HVAC Services Can Solve This Problem

We recommend contacting a professional HVAC service to help you if the freezing continues to happen after you install a new filter or if you notice that the motor or blower drive belt is broken.

If you are experiencing frozen evaporator coil issues, please contact Valley Service. Feel free to reach out to us to learn more about our services and what to do when AC coils freeze up.