How to Repair a Frozen Up Central Air Conditioner Unit

Whether you have a window unit or a central air conditioner unit, find out how to repair a frozen up system quickly and save some money.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• water hose
• air hose
• vacuum cleaner

1. Defrost the Unit
   
   First thaw your unit by turning it off. Turn the breakers off to the unit to avoid short circuits. Tape a tarp or large trash bag under the unit to catch the water as the ice thaws. After the ice thaws, hand dry the unit and let it stand to dry for 24 hours. Inspect the unit to ensure it's dry before turning the power back on.

2. FANS
   
   Verify the outside fan and inside fan units are working and turning. DO NOT check the unit by sticking your hand in them.

3. FILTERS
   
   The first thing to check are the filters on the indoor unit. These should be changed every 3 months and can be purchased from your local home improvement store for a price of $3 to $15. Some allow air flow in only one direction. Make sure air is able to flow through the filters and into the unit.

4. COOLING FINS
   There are cooling fins on the unit inside and outside. These are thin strips of metal that are easily bent. You want to be careful to NOT bend these.
   
   With the power to the unit off, use a medium pressure hose to wash dirt from the fins in the outside unit. Trim grass and remove debris from around the unit.
   
   Clean the inside unit using a lower pressure air line or a vacuum cleaner. Use a flashlight to check the fins. If light can pass through the fins then they are clean.

5. COOLANT
   
   The main reason units freeze up is low coolant. Contact an HVAC technician to check the charge of your unit and add coolant if needed. A repair person can be found in your local phone book or newpaper ads.
   
   Keep an eye on the unit, if it starts freezing up again or looses it's cool air ability, then you probably have leak.

6. REPAIR COSTS
   
   With any repairs you must weight your options. If you do all the cleaning yourself it'll save you from paying an HVAC tech which can run $80 just for cleaning the outside unit with a hose.
   
   A tech may also tell you he needs to check for leaks before you fill your system. Coolant can run as high as $40/lb. Again this is a decision you will need to make... pay for the leak test and not have a leak or pay for the test and reduce the risk of loosing all the $40/lb coolant you're getting ready to buy. That's a risk you will have to weigh. It's one I've taken and won.
   
   Always ask if the work is guaranteed. Get a receipt for your work. Verify all the work is listed.

Tips & Warnings

• Research you problem online.
• Use a certified HVAC technician for services.
• Outside air units have a capacitor. They hold energy even when the power is off. Never try to do electrical repair on any unit unless you are a trained professional.

[plumberi]

on 10/9/2009 Good information. Thanks 5*

[lawyerlarry]

on 4/29/2009 Any ideas on rebalancing vents? It can be so cold downstairs and warm upstairs.

[bkr9988]

on 9/15/2008 "UNTHAW"!!?? Does that mean that you want to FREEZE it again? Last time I used the word Thaw, I understood that it meant "to make unfrozen". I have used the term myself and quickly realized that it didn't make sense. Let's reverse the trend toward illiteracy. We'll see how long it takes to thaw my a/c unit. Thanks for the tip.