There is nothing more frustrating than coming home after a hot day in the sun, only to discover your air conditioner isn't working. One of the most common reasons for AC repair is the unit freezing up. There are several reasons why this problem may occur; some of the repairs you may be able to do on your own, but some can only be resolved by a professional HVAC technician.
There are a few things you can try on your own to unfreeze the air conditioner. Before you attempt to do any type of AC repair on your own, it is important to make sure the power is turned off to avoid the risk of injury. Some DIY repairs to prevent the air conditioner from freezing up may include the following.
Check the filter-a dirty filter will often cause clogs in the coil, which may cause ice to form on top of the unit or on the coil and fan. The filter is generally located in the return vent. To change the filter, turn the air conditioner off, remove the old filter and replace it with a new one and turn the air conditioner back on.
If there is a layer of ice on top of the unit, it may only need to be thawed out. To defrost the coil, turn the thermostat off and the fan on. Leave only the fan running for several hours. After the ice has melted, turn the thermostat on to see if the unit is working again.
If you have been unsuccessful in getting the unit to work by changing the filter and/or thawing the unit or if these steps work, but the unit quickly refreezes, you should contact a professional HVAC technician to inspect the unit and make the appropriate repairs. Some of the most common causes of an air conditioner freezing that require professional repair may include:
Outdoor temperatures-it is common for an outdoor air conditioning unit to not work as well as it should if the outdoor temperature falls below 60 degrees. As the outside temperatures drop, it causes moisture from the low temperatures to puddle on the coil and eventually freeze. If this is the problem, the HVAC technician won't be able to control the outside temperature for you, however, they can install an ambient temperature control device on the system, which will allow you to use the AC unit in milder temperatures.
Insufficient air flow-the most common cause of insufficient air flow is a dirty filter, but if you have changed the filter and there is still an insufficient air flow, it may due to clogged ducts. An HVAC technician will be able to disassemble the air conditioner and clean all parts and components to remove any obstructions.
Low refrigerant-if your air conditioner is low on Freon it will cause the coil to freeze up, which may lead to damaged parts. It is important to know that there are state rules and regulations regarding the use and disposal of Freon, so you will need to contact a professional HVAC technician to check the Freon and add more if needed.
Defective blower-the blower (fan) for the cooling coil may stop if the blades are restricted due to ice or if the fan belt that is attached to the blower is old and/or damaged. A professional technician will need to take the unit apart and repair the fan or the fan belt.
The best way to avoid having the air conditioner freeze up when you least expect it (and when you need it the most) is to have routine maintenance and servicing on the unit before the beginning of each summer. During the routine maintenance, all components of the air conditioner will be carefully inspected to ensure everything is in good working order, eliminating the risk of the AC unit freezing up.