A frozen air conditioner fails to cool your home properly. When the refrigerant inside an air conditioning system falls below 32 degrees Fahrenheit, humidity on the evaporator coil freezes. The coils become encased in ice, and the air conditioner fails to cool the home sufficiently. Homeowners can perform routine checks and maintenance, but trust electrical repairs, leaks, and replacement of faulty devices to the pros. Once you discover a frozen unit, turn off the system and turn on the blower to help thaw the evaporator coils. Feel the air coming out of the supply registers. If it feels warm, the evaporator coils may be iced over. Turn off the air conditioner and open the access panel to the evaporator. The panel is located in different spots for different manufacturers, but are typically near the furnace system inside the home. Small hex-head screws hold the panel in place . In severe cases, the ice may be visible outside the unit. Examine the copper coils. If they are encased in ice, the air conditioner is frozen.

Do not attempt to clear the ice by hand. That could damage the air conditioner's components. Check the filters located either in the air conditioner’s plenum, or at the cold air return grate for the home. If the filters are dirty, replace them. Look at the coils as well as the cooling fins around the evaporator. If they are coated with dirt, clean them using a soft plastic brush, such as a toothbrush, and a light touch. The fins may bend with too much pressure. Make sure all the air conditioning supply registers are open in each room the unit supplies with cold air. Blocked registers restrict air flow, which causes the temperature inside the evaporator to increase. Time the air conditioner cycle once it has thawed and you’ve turned the unit back on. It will cycle for a long time until the house reaches the thermostat setting, but should then shut off. If the unit continues to run, the electrical contactor in the outside portion of the unit may be damaged or its fuse may have blown.

Call an HVAC service person to check the unit and make repairs. Call an HVAC service person after you’ve checked all the registers, coils, and filters. The unit may be leaking refrigerant, the replacement of which must be performed by a licensed repair person. Things You Will Need Nut driver and sockets Air filter Soft plastic brush Warning References HVAC Parts Outlet: Troubleshooting a Frozen Evaporator CoilHorizon Services: Help! Photo Credits Jupiterimages/liquidlibrary/Getty Images Suggest a Correction If your air conditioner seems to be losing its cooling ability, the problem may be as simple as frozen or clogged air conditioning coils. Other causes of reduced cooling include restricted air flow and low refrigerant. Even though you may not be experienced in AC service, you can fix all three of these probable causes in several easy steps. Step 1 - Thaw Frozen Condenser Coils Find your electrical breaker box and turn off the switch that controls power to your air conditioner, and allow the coils to thaw.

Depending on the ambient air temperature around your condenser unit, it could take up to 24 hours for the coils to melt any ice that is plugging them. Step 2 - Dry the Air Conditioner Coils Once your condenser has had time to thaw completely, remove any pooled or standing water and use a towel to dry any remaining moisture that may remain on the machinery.split wall air conditioner units Step 3 - Turn the Air Conditioner's Fan Onlife expectancy of home ac unit After turning the breaker switch on again to restore electricity to your AC, find the thermostat that controls your unit. 5 ton cooling unitSet the thermostat control so that only the air conditioner's blower, or fan, is operating. The fan will help melt any ice or frost clogging the coils by circulating air through them.

Step 4 - Heat the Condenser's Coils You can speed up the thawing process by using a hand-held hair dryer. Be sure when you use this method of heating that you switch the dryer setting to low heat. A heat setting that is too high can crack the condenser's coils. Step 5 - Check Vent Filters Vent filters, when clogged with dirt and dust, are likely to reduce air flow and conditioner's ability to cool your house. To maximize cooling efficiency, you will need to check your vent filters. If they are dirty or clogged, replace them with new ones. If you don't have extra filters on hand, you'll find them at most hardware or home improvement stores. Step 6 - Add Coolant Another condition that often reduces cooling efficiency is low coolant in your AC unit. The best way to check for low coolant, and add it when necessary, is to buy a coolant installation kit which you can usually find at a nearby home improvement store. Most of these kits will include directions for adding the coolant.

Step 7 - Test the Cooling Capacity Once you have completed the rest of these steps, test your air conditioner's ability to cool. Turn the thermostat setting to "cool," wait a few minutes, and then test the air coming from the vents. If the air blowing through the vent is as cool as you would like it to be, you can rest assured your repairs were successful. How to Clean Air Conditioner CoilsI was a bit surprised to see this question, since this should be readily available information elsewhere, so I did a short search to see if there is a problem finding out the answer.  It turned out there is, in that there are a lot of incorrect or incomplete answers out there.  The best answer I came across was this:"All air conditioners try to freeze up, that is the goal of the refrigerant... to chill.It is the design of the system that prevents this freezing up from occurring.There are three basic reasons for air conditioner freeze ups:1) The two most common causes of insufficient air flow are dirty filters and under sized ducts.

A dirty filter limits air flow which in turn allows the cooling coil’s temperature to drop below freezing. Replacing the filter, monthly, usually alleviates this problem. Under sized ducts will also cause the system to freezeBecause it also limits the amount of air flowing over the cooling coil. This results in lowering the coil temperature and allowing the humidity in the air to collect on the coil and freeze.2)Refrigerant charge. The refrigerant system teeters on a delicate balance. If the system is not charged correctly, the system will not function properly. This malfunction may result in the poor cooling output and/or freezing up. Only a qualified, certified service technician can properly test and charge a refrigerant system.3) Outdoor temperature. If night time temperatures are too low, the system will not operate properly, and freeze up may occur. The outdoor unit does not function well in temperatures below 60 degrees F. A special “ambient temperature” control must be installed to allow the unit to run properly in cool temperatures, or you may open your windows and save energy."