Why Your air conditioner may not be working.
Home air conditioning units can freeze up for a number of reasons, but there are some remedies that a homeowner can perform to fix the problem. Causes such as a small leak in the refrigerant line or a bad compressor may take a phone call to the local air conditioning service. As soon as a frozen coil is noticed, the first act is to shut off the system and let the iced up coil thaw on its own. Do not apply any form of heat to the refrigerant coil
Clean the System
Replace or clean all air filters in the air conditioning system after the ice has melted. Chances are you will also be cleaning up water from around the window unit or inside the interior coil. Use a vacuum cleaner and remove any dirt or debris from the coil after it has fully dried. Attach the brush to the end of the vacuum hose, and carefully run it across the coil in the same direction as the fins. Take care so as not to damage the aluminum coil. Place a new filter or the cleaned one back into the filter holder. Turn the unit back on.
Check the Fan
Watch the operation of the blower fan. The fan should be moving the air from the intake vents or the lower portion of a window unit. If the fan does not operate, stop the unit. The blower’s fan motor will have to be replaced, or a relay is bad. Check all intake vents on the AC system to be sure that there is no obstruction in front of the registers Open all exhaust vents on the AC system as well. Closed vents will restrict the airflow across the coil and may be a cause of the freezing coil. If the fan is operating properly and all vents are unrestricted, check the outside line at the outdoor coil.
Outdoor Coil and Some Extras
Observe the lines that are coming from the outside coil and that lead back into the house. One of the lines should have some minor condensation on the copper tubing. If the line is icing up, it is a good indication that there is a small leak in the system. Low refrigerant levels will cause the line to be overworked and create a freeze plug in the refrigerant line. Shut the unit off and call a service technician.
Running the unit for a very cold temperature indoors can also cause the coil to freeze up prematurely. The outside coil maybe experiencing problems due to low temperatures outdoors and really cool temperatures indoors. Adjust the thermostat to a higher level. If you want the temperature to remain cold indoors while the outdoor temperature is below 70 degrees F, certain accessories will have to be added to your system.But most if these tests should be performed by a licensed HVAC air or heating contractor