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4 Reasons why AC Compressor Does not Seem to Work While Fan is Running

When the scorching heat of summer hits you, the last thing you would want is a dysfunctional AC. The last time you checked the AC before summer, the fan was running perfectly OK. But did you check the AC compressor? Probably not! Now in the middle of summer, you discover the AC compressor is not working although the fan is running. Well, don’t get spooked out on this for this is quite a common issue in every house.

The function of the AC compressor-

It compresses, as you can guess from its name already, the refrigerant fluid so that it is converted into a liquid from the gas. While doing this the heat from inside your home is carried away by the compressor outside leaving your indoors cool, refreshing, and relaxing.

Inappropriate maintenance of the AC compressor sometimes can lead to its malfunctioning.

An air conditioning unit can still appear to run with a malfunctioning HVAC compressor.

AC unit is equipped with a pair of fans, which still can run even in case of a malfunctioned compressor.

Below are four top reasons which could potentially cause a Compressor to malfunction.

Non-maintenance of coil and filters

Is the air filter of your AC unit dirty? or the condenser coil? This can be the starting point of compressor turning faulty. Dirty air filters and condenser coils put extra stress on the AC compressor. It will then overheat and the whole HVAC system will shut down.

Clogging of the air filter with dirt or debris will bring a significant reduction in the airflow and put more pressure on the compressor. Continued overheating for an extended time could result in irreversible damage to the AC compressor.

The problem in the capacitor and starter relay

Capacitor and Starter relay supply power to the AC compressor and fault in these two components are among the most common causes of problems in your compressor. How does your compressor start and run? By the action of the capacitor. Who runs the blower motor and outer fan? Capacitor again. The power is transmitted to the AC compressor from the capacitor by the starter relay.

Do you ever hear a humming sound coming out from your AC system unit? Well, this happens when the compressor tries to receive power from a non-operational capacitor. Replacing them is the only way out when such a problem occurs. Don’t delay. Get the problem fixed at the earliest. Be assured the parts won’t cause your pocket to burn as these come cheap and are easily available in the market.

Dead Compressor

Is your HVAC unit all or any of its components been overheating for some time now? Be ready for a compressor fiasco! Come summer and a problematic capacitor or a prolonged overheating of any of the components of the HVAC unit can stress the compressor even can lead to its death.

Power problem

Fluctuations or snapped wiring or disjointed power connections can often lead to the AC compressor in the outside unit fail to start properly. This results in the compressor failure, but the fan continues to run as before. This is because the central unit inside does not face any power problem. The wiring, which connects the inside and outside units, needs to be checked in such cases. Often circuit breaker trips too in case of frequent outages. Using a power stabilizer and multi-layered protection is always advisable.

With a faltering AC compressor, you are most likely to experience warm and dry air circulating in your room accompanied by strange noises. You will also find the outdoor unit shaking uncannily if your AC compressor is not working. Do not go by the running fan as it does not always indicate a perfectly functioning AC compressor.

What to do when the compressor turns faulty?


  • Wash condenser coils at regular intervals
  • Wash, clean, and replace the air filters when necessary
  • Clean the supply vents and make them free of any obstruction or blockage regularly
  • Replacing capacitors and starter relays, the instance you detect a humming sound coming from the unit
  • Check electric wiring periodically for a blown fuse or tripped circuit breaker
  • Inspect the AC before summer season so that you are not faced with issues in the middle of summer
  • Take the help of AC technicians for checking things out. These are better not tried as DIY activities.

Once compressor turns faulty:

  • Replacing the dead compressor !
  • Always rely on an HVAC expert to replace the part or compressor as these can be tricky and doing it without knowledge can result in even bigger damages

Now that you know there is nothing spooky in your HVAC system when you find the fan running although the AC compressor is not working, make sure you get it checked by professionals and do as they suggest you. Get your AC compressor problem fixed and enjoy the summer while staying at home!

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