How to Fix a Frozen Central A/C

Take a refrigeration recovery machine and use it to reclaim all of the refrigerant inside the A/C unit. Connect refrigeration gauges up to the unit and apply 200 PSI of dry nitrogen to the lines.

Examine the refrigeration tubing for a leak. Remove the insulation from the tubing. This will expose all of the bare copper so that you can examine it for corrosion or areas that have been worn down. Apply a small quantity of soap bubbles to any area that looks like it may have a leak.

Release the nitrogen from the lines once the leak has been found. Use a torch and brazing rod to seal the leak shut. If the leak is a result of corrosion you may need to replace the copper section. You will have to cut out the section of copper with the leak and replace it with new tubing and couplings.

Check the unit to make sure you have properly sealed the leak. This is done by hooking up the refrigeration gauges again and filling the tubing with 200 PSI of dry nitrogen. Allow the nitrogen to sit in the tubes for two to three hours. If the pressure remains at 200 PSI the leak has been sealed properly. If the pressure drops you may need to check for a second leak.

Remove moisture from the system by hooking up a vacuum pump to the copper tubing. Refill the copper tubing with the proper amount of refrigerant. The amount your unit requires will be listed on the service panel. Put new insulation on the copper tubes.

Turn on the air conditioning unit and make sure it is working properly.