If the fan on a window air conditioner suddenly stops after running for a while, there could be several possible reasons for this issue. Some of the common causes include:
Overheating: Window air conditioners have thermal protection mechanisms that shut down the fan motor if it becomes too hot. Over time, dust and debris can accumulate on the unit's internal components, obstructing airflow and causing the motor to overheat. This can trigger the thermal protection to kick in and shut down the fan.
Faulty Fan Motor: The fan motor itself may be faulty or experiencing electrical issues, leading to intermittent operation or complete shutdown. It could be due to worn-out motor bearings, a damaged motor winding, or a faulty capacitor (if the motor uses a capacitor for starting).
Electrical Issues: Problems in the electrical circuit, such as loose wiring connections, a blown fuse, or a tripped circuit breaker, could interrupt power to the fan motor, causing it to stop running.
Control Board Malfunction: The control board in the air conditioner is responsible for managing the various functions, including fan operation. If the control board is faulty or damaged, it may lead to irregular fan behavior or a complete shutdown.
Thermostat Problems: A malfunctioning thermostat might not be sending the proper signals to the fan motor, causing it to stop unexpectedly.
Capacitor Issues: The capacitor in the fan motor circuit can sometimes fail or lose its capacity to start the motor, resulting in the fan stopping.
Dirty or Clogged Air Filter: A dirty or clogged air filter can restrict airflow and cause the unit to overheat, leading to the fan shutting down.
Low Refrigerant Levels: In some cases, low refrigerant levels can cause the evaporator coil to freeze up. When this happens, the fan may stop to avoid further freezing and damage.
To troubleshoot and resolve the issue, you can try the following steps:
Turn off the air conditioner and unplug it from the power source for a few minutes to allow the motor to cool down. Clean or replace the air filter during this time.
Check for any loose wires or connections in the unit. If you find any, securely reconnect them.
Clean the air conditioner, including the fan blades, condenser coils, and other internal components, to ensure proper airflow and prevent overheating.
If the problem persists, it's best to contact a professional HVAC technician to diagnose and fix the issue. They have the expertise and tools to identify and repair specific problems with the fan motor or other electrical components.