Air Conditioner Coils Frozen

by Dave The Handyman on January 23, 2010

Thank you for finding my site – and if you landed upon this page then you are more than likely have a frozen air conditioner, and you are wondering what the hell you can do to fix it. Not only that, if the coils and pipes of your AC are frozen, that also means that you are not getting any cold air, so you are probably sweating to death as you read this, don’t worry, I may be able to help you solve your problem of fixing your frozen air conditioning.

Is your air conditioner frozen both inside and outside?

If so then this usually indicates a blockage somewhere in the system. Most of the time this is due to a dirty air conditioning filter, which is located usually near the air handler coils. For those of you that do not know the air handler is located inside, and warm air is sucked in through the coils, so there is always a constant suction of air going on in your home when the air conditioner is running.

Changing your air filter regularly can prevent a frozen air conditioner

This also leads to dust and the millions of other particles that are in the air getting caught up in the air filter, well most of them anyway. If you go a long time, like 6 months or so without changing your air filter then this dust and other crap is going to build up and not let the air conditioning work. Now there is cold ass freon going through the coils of the air handler waiting to grab some heat from the warm air inside, when there is no heat to grab the line is going to freeze, all the way from the inside to the outside.

Make sure you have an air filter installed

If you don’t then the same thing is going to happen, except the evaporator coils are going to clog up this time. If this happens then you will need to clean the evaporator coils with some type of professional coil cleaner and a fin brush, or something that is soft and will not damage the coils such as a toilet scrub brush. I will cover how to do this in a future post as it is a whole other can of worms to go over. Another thing that you are going to want to check is that the return vent is not blocked, this is where the air is sucked in at and usually on the other side of it is the air filter. Many people will leave laundry baskets and other stuff in front of the return vent, this is a no-no, there should be nothing in front of return vents to ensure proper air flow.

If neither one of those solved the problem then the problem may be outside. If you outside coils are covered in shrubbery or leaves, or just a bunch of crap, then it is stopping the heat from being discharged, which will also cause an air conditioner to freeze up.

Another thing that may cause an air conditioning system to freeze up is a bad blower motor, which is located inside of the air handler. If that is unable to move the air,  then your compressor is going to keep cycling refrigerant through the system, but is not going to absorb any heat, causing the unit to freeze up.

Also, if it is 60 degrees outside, and you set your thermostat for 55, your unit may also freeze up too. Hopefully not too many people on here are doing that, you would be surprised though.

One last thing that will cause an A/C to freeze up is low freon, professionally known as refrigerant. If this is the case then you will have to get a certified HVAC technician that is able to handle freon and use gauges to come out and check the refrigerant levels on your unit.

{ 5 comments… read them below or add one }

Darla Garrett June 15, 2010 at 12:48 pm

My ac/heat pump seemed to be working fine for the past week. My husband sprayed off the heat pump to get the dust off of it about 5:00 pm yesterday. We woke up to a frozen up ac, both inside and outside. Any suggestions?

Alicante Car in Rental June 23, 2010 at 11:20 pm

My ac/heat pump seemed to be working fine for the past week. My husband sprayed off the heat pump to get the dust off of it about 5:00 pm yesterday. We woke up to a frozen up ac, both inside and outside. Any suggestions?
+1

Nick July 11, 2012 at 10:31 am

My unit has been freezing on and off for 2 months now. My landlord has topped up the Freon 6+ times and it will work for a couple of day and then freeze up. We’ve changed filters, cleaned off the intake and the coils, even replaced the compressor and it still freezes. They also insist there is no leak in the system. But something must be wrong- what else could there be? Could there be something periodically blocking flow of R21? If so, how do you test or fix that?

Dave The Handyman July 20, 2012 at 1:29 am

Nick, more information is needed…for instance if you have txv metering device thats not throttling properly that could also cause your unit to freeze up,

william October 3, 2012 at 3:10 pm

Hello,my question is my coil is getting frozen only in the bottom.the coil is clean,my filter is clean.my gauges are fine 70 and 250.i don’t know what’s wrong.

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