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frozen air conditioner

Why Do Air Conditioners Freeze Up?

It can be quite surprising to discover ice forming on your air conditioner in the middle of summer, but this is not an unusual AC problem! There are a number of problems that can cause air conditioners to “ice up” or “freeze up.” While you can perform some minor troubleshooting on your own, the problems that require a repair should be handled by an HVAC technician.

If ice is forming on your air conditioner, it’s probably due to one of these four reasons.

1. There’s a Lack of Airflow Across the Evaporator Coil

2. Your AC Is Low on Refrigerant

3. The Coils Are Too Dirty

4. The Blower Fan is Broken or Damaged

Rather just contact a professional? The NATE- and EPA-certified cooling technicians at Monarch Home Services are on call 24/7 for emergency AC repair. With offices in both Bakersfield and Fresno, our technicians cover the South Central Valley.

1. There’s a Lack of Airflow Across the Evaporator Coil

How does a lack of airflow lead to ice formation? The two seem unrelated--unless you learn about the way air conditioners work first.

Your air conditioner draws in the warm air from your home, cools that warm air, and then pushes that cooled air back into your home. During this cooling process, condensation forms. If there is not enough warm air coming into your air conditioner from your home, that condensation won’t stay liquid and will start to freeze, forming the ice you see on your air conditioner.

Here are some common reasons why your air conditioner might not have adequate airflow, along with tips to troubleshoot the issue:

  • The air filter might be clogged with dust. Replace your air filter with a new one.

  • Something could be blocking your return vents. Make sure that all of your vents are free of obstructions.

  • Your ducts might be closed or blocked. Make sure your dampers are open, and test your vents to see if you can feel air coming out. If you can’t, it’s best to contact an HVAC technician.

2. Your AC Is Low on Refrigerant

Your air conditioner uses refrigerant to remove heat from warm air, thereby cooling it. If your system has a refrigerant leak or if the refrigerant was not properly charged during your AC’s installation, it’s going to create a lack of pressure in the system. That lack of pressure makes the refrigerant absorb an excessive amount of heat that can lead to refrigerant lines and coils freezing over.

To avoid damage to your AC’s compressor, shut off the unit, and call an HVAC technician to fix the refrigerant leak. Refrigerant issues require professional training and should not be handled the DIY route.

3. The Coils Are Too Dirty

Your air conditioner not only cools the air inside your home, but it also dehumidifies it. As your air conditioner draws moisture from the air, condensation forms on your AC’s coils. When everything is functioning properly, this condensation falls and is collected in the drip pan.

When the coils become too dirty, they are not able to transfer refrigerant to the heat pump as effectively. This makes your AC system work harder to cool the air, which can cause the condensation on the coils to freeze before reaching the drip pan.

If your AC’s coils are frozen, shut off the unit to avoid damaging the compressor, and contact an HVAC technician to clean the coils. It’s a good idea to have the coils cleaned on a regular basis, not only to avoid the freezing issue but also to keep your AC running efficiently for as long as possible.

4. The Blower Fan is Broken or Damaged

Your AC’s blower fan plays a key role in the airflow and air pressure that your air conditioning system needs in order to work properly. For instance, the blower fan helps to draw out the warm air from your home so that cooler air can take its place.

When the blower fan is not working, this can cause excess condensation to form and freeze on your AC’s coils. A broken blower fan can also result in a frozen refrigerant line.

The motor of your blower fan is probably malfunctioning if:

  • The fan will only blow at certain speeds.

  • There is little or no airflow coming from your vents.

If broken, it’s likely that your blower fan will need to be replaced. If this is the case, it’s best to have the replacement performed by a trained professional.

If you’re experiencing poor airflow or a frozen air conditioner after changing your air filter, you will probably need the services of a professional HVAC technician. The friendly and helpful experts at Monarch Home Services are ready to assist!

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