How To Repair Air Conditioner That Does Not Blow Air

About this repair:
  • Rated as REALLY EASY
  • 10 repair stories
  • 4 step by step videos

Fan and Fan Motor

If your window air conditioner is not blowing any air, the problem could be the fan or fan motor. In a properly working air conditioner, the fan will draw air over the cold evaporator coils and then re-circulate the air back into the room. If the circulating fan is not running or running too slow, little or no air flow over the evaporator coils will allow them to become too cold and frost or ice can form, restricting the air flow even more. The fan and motor are located inside the cabinet so removal of the cover will be necessary to perform any checks. Make sure that the fan motor will turn easily and that the blades are not damaged. If the motor is seized or if the fan blades are damaged then they will need to be replaced. If the motor turns easily it may still be defective or it may not be getting power from the controls. These tests are more complicated and should be performed by a qualified person who is comfortable with the use of a multi-meter.

Fan Motor Capacitor

Most window air conditioners utilize a run capacitor in the fan motor circuit. If the motor hums or turns slowly you may have a defective capacitor. The fan motor and capacitor are located inside the cabinet and access will require removal of the cover. Verify that the motor and fan can turn freely and check for any burnt or damaged wiring to the motor and capacitor. If the capacitor does not show any visible signs of damage you will require a qualified person to check it with special test equipment.

Electronic Control Board or PCB Assembly

If your air conditioner is running but not blowing any air and you have inspected the air filter and fan motor and found them okay, then you may have a problem with the control board. Sometimes referred to as the PCB, this is an electronic control board that operates the fan motor and compressor circuits using relays mounted on the circuit board. The power output from the relays can be checked with a multi-meter, but this should only be attempted by a qualified person. If the on board relay is defective, or if the processor circuitry is defective then the control board or PCB will need to be replaced.

Air Filter

A common cause of window air conditioners not blowing any air is a restricted air filter. In a properly working air conditioner, a fan will draw air over the evaporator coils, where it is cooled, and then be re-circulated back into the room. If the air filter becomes dirty or clogged, there will be little or no air flow over the evaporator coils, which will cause them to become too cold and frost or ice will form on them, causing the air flow path to be completely restricted. This can result in no air at all being circulated into the room. The air filter is positioned in front of the evaporator which is located behind the front grille. Clean or replace the filter as often as required. If the evaporator coils are very dirty then cleaning them with soapy water and a soft brush will be required and we also recommend changing the filter at the same time.

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