Air Conditioner Problems - As an HVAC technician I am aware of all the problems air conditioners can develop. Therefore, you will get a unique perspective on air conditioner problems. And hopefully, how to avoid these problems. Trane Condensing UnitAir conditioners have become a norm in today’s society. Forty or fifty years ago air conditioners were considered a luxury. Now there are building designs where the occupants must rely on air conditioning to remain comfortable.

Additionally, with higher energy costs it is important that our air conditioners are maintained. Hence, a properly maintained system uses less energy and repair costs are lower and less frequent.

Air Conditioner Problems - Motors and Capacitors

Problems that can be found in residential air conditioners include different components. There are bad motor run or start capacitor on either the blower fan motor, the condenser fan motor. Or the compressor for the air conditioner or heat pump. Capacitors are needed for the commonly used in HVAC PSC electric motors. These motors are used in a lot of HVAC equipment. Probably because of the PSC motors low cost, efficiency and available starting and run torque.

The PSC electric motors are the backbone of air conditioning and heating systems. The capacitor is a necessary component of the PSC electric motor. Capacitors are rated and measured in microfarads. The smallest PSC motor typically uses a 3 to 5 microfarad capacitor. Large single phase electric motors found in compressors use 100 to 300 microfarad rated capacitors and can vary. This gives it the starting torque the compressor needs to start.

Handle With Care – Air Conditioner Problems

Capacitors need to be handled with care. They hold a charge in them even after being disconnected from the air conditioner. The higher the microfarad rating the bigger the shock from the capacitor if it discharges. Therefore be very careful around capacitors even when they are disconnected. A capacitor can be discharged using a resistor or a source of resistance to discharge the charge inside the capacitor.

A special meter is needed to test the capacitor. Not all multimeters have the function to measure microfarads. You may need to purchase a special meter that will measure microfarads. This will allow you to see if the capacitors are with the range of the microfarad rating. This should be at least 10% plus or minus of the rating on the capacitor. If it is not in this range then it needs to be replaced. If the PSC electric motor quits working or works abnormally then it is prudent to check the capacitor. It is possible the capacitor is bad and needs to be replaced.

Common Issues – Air Conditioner Problems

The next common air conditioner problem you may encounter is bad fan motor. A bad fan motor can be the result of a bad capacitor.  This is not the only thing that can be the cause of a bad fan motor. However, it is a culprit in some cases. The air handler blower motor and the condenser fan motor are motors that commonly go bad in HVAC equipment. Replacement motors are readily available in most HVAC supply houses. Sometimes other specialty supply stores carry HVAC electric motors.

The most common motor failure out of the two is the condenser fan motor versus the air handler blower. The probable reason for this is that the condenser fan motor operates outside. Outside in the environment and is susceptible to the temperature extremes and moisture. While the air handler blower operates in a more friendly environment that is typically conditioned and much drier. The extremes of the outdoors take a toll on condenser fan motors and leads to premature failure.

Spring Start-up

The first time you start the air conditioner in the Spring it is prudent to check the condenser fan motor. Check it to make sure it will start the first time after sitting idle all winter. Physically verify that the fan is running and working properly. Some condenser fan motors for air conditioners sit all winter and do not turn. This allows some rust to build up in the motor and this causes problems. So when it comes time to start it will not spin even though the condenser fan motor is getting power. The condenser fan motor is frozen with rust and will not turn.

If you are there to physically see the fan start (or not start) then you can take action. In situations like this when For a condenser fan motor that fails to start you can give it a boost. I give it a quick push by sticking a long screw driver down into the blade to get it started. In some cases, this will work like a charm and condenser fan motor works throughout the season. However, sometimes the fan was already burned up when I arrived and needed to be replaced.


There are other problems that can occur with your air conditioner and we will cover them in the future. In another air conditioner problem article. Some problems we cover in other categories at High Performance HVAC such as HVAC Refrigeration Category.

Air Conditioner Service and Repair

Air Conditioner Problems - High Performance HVAC

Air Conditioner Problems

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