Before calling for air conditioner repair, the user should make sure the unit is plugged in and the circuit breaker or fuse is turned on and working properly. He should also ensure the thermostat is set to an appropriate temperature.
If there is ice on the unit, the problem may be caused by a malfunctioning blower belt. The owner should check the belt to see if it is too loose, broken or cracked and replace it if necessary. The unit should be free of ice before restarting. Ice on the unit may also be caused by dirty coils or a clogged filter. The user should clean these parts and allow any ice to melt before restarting the air conditioner.
If the outdoor temperature is less than 70 degrees Fahrenheit, the compressor of a window air conditioner may not switch on. Lower outdoor temperatures may cause the indoor coil to frost or freeze over, which limits the cooling capacity of the unit. Any obstructions to the air conditioner's output, such as curtains or blinds, may cause the unit to not cool efficiently and should be removed. Very hot rooms takes longer to cool, as heat stores in walls, furniture, rugs and draperies.