Why AC Compressor Not Working but Fan Is Running?

Fan is running but compressor is not working


The air conditioning system relies on a crucial component known as the compressor, responsible for transporting heat away from the house by compressing the refrigerant. This process involves converting the refrigerant from a gaseous to a liquid state, with the refrigerant temperature consistently surpassing the ambient temperature. Efficient heat transfer from a warm to a cooler environment is facilitated by a properly maintained and functional compressor. In cases where the air conditioner malfunctions, the HVAC compressor is often the root cause. The question is why AC compressor not working but fan is running.

Summer temperatures can be challenging, and a malfunctioning HVAC compressor can worsen the situation. Instead of providing comfortable, cool air, an operational air conditioner may only produce warm and dry air when the compressor fails. The frequency and duration of HVAC system operation can contribute to compressor problems. Nevertheless, if the fan is operational while the compressor is not, there’s no need to panic. The following explains why this issue may occur.

Common Reasons for AC Compressor Malfunction:

1. Dirty Coil and Filter:

Accumulation of scale or dirt on the evaporator coils, filter, or condenser coil can lead to the unit’s shutdown. A clogged air filter and dirty evaporator coil reduce airflow, increasing compressor pressure and causing overheating. Regular maintenance, including cleaning the condenser coil and removing blockages, is essential.

2. Capacitor and Starter Relay Issues:

Essential for the compressor’s power supply, starter relays and capacitors are frequent culprits in compressor failures. The starter relay transfers power from the capacitor to the compressor, and a buzzing sound may indicate a faulty capacitor. Fortunately, capacitors are relatively inexpensive and straightforward to replace.

3. Dead Compressor:

Faulty capacitors or overheating units might lead to a dead compressor. In such cases, professional replacement is necessary.

4. Power Problems:

If the compressor’s outdoor unit lacks power, even if the fan is operational, the compressor will not function. Checking wiring connections is crucial in such situations.

Possible Issues When Compressor Fails:

– Warm air from a running fan.
– Frequent tripping of the circuit breaker.
– Complete halt of the compressor.
– Unusual noises and shaking from the outdoor unit.


Regular maintenance is the key to preventing most problems before they escalate. Compressors consist of easily replaceable parts, and routine inspections facilitate the early detection and replacement of defective components, preventing air conditioning compressor issues. K2 Mechanical offers high-quality products and affordable maintenance and repair services. If you require air conditioning service, contact us promptly.

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About the author


I am Ben , a seasoned HVAC specialist with over 6 of experience in the HVAC industry. I holds HVAC Certification and has a proven track record in providing expert advice on HVAC systems.

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