Help! My A/C Is Frozen.

May 31, 2018

It may happen at the beginning of the season or after a few months of operation, but many homeowners find that their A/C system has frozen.  To some this is a yearly occurrence while others it’s a first time surprise.  Here is a guide to help you understand why it has happened and how to prevent it from repeating.

There are only two things that will cause a residential A/C system to freeze:  
1- Lack of airflow
2- Lack of refrigerant

Lack of Airflow
           The most common cause for lack of airflow is a dirty filter.  Negligence in replacing your air filter will cause reduced airflow which will lower your air conditioner’s coil temperature below freezing.  When you check your air filter, hold it up to light.  If it's difficult for light to shine through you can expect airflow is having the same trouble.  
           If the filter has been neglected long enough, or the system was run without a filter altogether for an extended period of time, it may be possible that the indoor coil is clogged with dirt and debris creating an air dam.  In the same way, the blower wheel may also have excessive dirt and debris.  The blower wheel has scoops which “throw” the air.  If these scoops are filled with dirt they can no longer move adequate airflow.  Imagine trying to swim with an open hand and your fingers spread apart.  Repairing these problems are more extensive and can require chemical cleaners to resolve the issue.  
           Another source of decreased airflow is having too many vents or ducts closed down or blocked.  Keep consideration when closing off ducts to an unused room or placing furniture over vents.  If enough ducts are restricted it’s like your system is trying to breathe through a straw.  It’s just too difficult.
           One more cause for lack of airflow is a failed blower motor.  The blower motor is what circulates air throughout your home.  If it breaks down the only repair is to replace the motor which can be expensive.  Dirt, debris, and excessive strain on your motor will increase the chance of premature breakdown which is why it’s so important to keep your filter clean.

Lack of Refrigerant
           The refrigerant in your air conditioner should be a sealed system.  It is not like putting gas in your car every so often to keep it going.  Unfortunately, far too many homeowners have to “top off” their system every season.  This is getting more and more expensive as the old R-22 Freon is getting phased out due to environmental concerns.  Leaking refrigerant is hard on your wallet as well as the environment because it destroys our ozone and has a high global warming potential.  
           Repairing a refrigerant leak starts with finding the source.  A professional can use an electronic leak detector to “sniff” out were it’s escaping.  Repairing the leak can be as simple as tightening a service cap or as extensive as replacing equipment.  As the cost of freon rises, it is becoming more recommended to replace your A/C system to prevent costly repairs with an obsolete refrigerant which is being phased out by the EPA.  In 2020, we will no longer have access to new R-22 and whatever is left in the market will be extremely expensive.   

        Remember, before any steps can be taken for repair it’s important to know that you must turn your A/C system OFF!  The system must COMPLETELY thaw before turning it back on or you will continue to form ice and put excess wear and on the equipment.  One of the hardest things on a residential air conditioner is continuing to pump refrigerant through a frozen coil.