If your home's HVAC system is blowing air, but it doesn't ever get cold even when you put the thermostat on its cool setting, then this generally signals a problem with the air conditioner's compressor unit. The compressor unit is the part of the system located outdoors; below is information on each of the three parts that most commonly cause problems:
The Run-Start Capacitor
The most common failure point in an air conditioner's compressor unit is the run-start capacitor. The capacitor is a small, round cylinder with four electrical connections on the top. Its purpose is to store electrical current to start the compressor's motor when you turn on the unit.
When run-start capacitors fail, they tend to expand at the top and take on a mushroom-like shape. However, they can also fail and not show any outward signs. The best way to determine if the capacitor is a problem is to test it with a voltage meter and see if it is still storing electrical current or not. If the contacts on the top don't show any current, then the capacitor needs to be replaced.
The Electrical Contactor Switch
When you set your thermostat to cool, this action should signal the air conditioner's compressor to turn on. The part that makes this happen is an electrical contactor switch. The contactor switch consists of two or three electrical contacts, and these contacts can be easily damaged by burning or pitting on its contact points from repeated use.
The contactor switch is located in the service panel of your air conditioner's compressor unit and can be tested using a voltage meter. Additionally, you can spot problems with the contactor by inspecting the contact points and looking for black burn spots or pitting in the metal plates. If the contact points appear dirty or corroded, then you can clean them; otherwise, the contactor switch needs to be replaced.
The Condenser Fan Motor
The condenser fan in your air conditioner's compressor unit has its own motor. This motor does sometimes fail, and when it does the condenser unit is no longer able to cool air.
The fan's motor is easy to locate because it is connected to the fan blades. The motor is sealed inside of a cylindrical case and you can easily determine if it is damaged, because when it fails it typically leaks bearing grease all over the outside of its case. If you see black oil on the outside of the fan motor, then the internal bearings have leaked out their grease and the motor has likely failed and needs to be replaced.
For more help, reach out to local air conditioning services.
