Why Does The Fan Keep Running On My Air Conditioner?

air conditioner fan that keeps running

A typical air conditioner cycle should last about 15 to 20 minutes. Then, the unit will take a break for about 7-10 minutes before the cycle starts once again. Units that operate well beyond that time frame indicate a problem that requires attention. Naturally, homeowners who experience this issue tend to ask us, “Why does the fan keep running on my air conditioner?”.

This article discusses what causes the fan on an AC unit to run continuously and what you can do about it.

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Why Does The Fan Keep Running On My Air Conditioner?

Here are several likely reasons your air conditioner’s fan fails to shut off:

  • It has a damaged fan.
  • There is a broken thermostat.
  • The air filter has a problem.
  • The fan switch was turned to “manual.”
  • It has dirty or frozen condenser coils.
  • Your home gets too much hot air. 
  • The unit is the incorrect size for your home.
  • You have old, broken, and problematic ducts.
  • The air conditioner has insufficient refrigerant.
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Cause #1: Damaged Air Conditioner Fan

image of an air conditioner fan repair

If you have an older air conditioner, the fan may be damaged, which may be why it won’t stop. Typical wear and tear can impact the fan as time passes. Build-up or debris near the motor will also wear it down. Excess accumulation will also cause the fan to crack and break, which won’t stop the unit. Instead, it will make the air conditioner work harder.

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Cause #2: Fan Switch On Manual

Different units have different wordings. However, if the fan is set to “ON” or “manual,” then air conditioner won’t turn off until you do it by hand. Make sure that the unit is set to “AUTO” and check if it starts to run a normal cycle. This means each cycle runs for 15 to 20 minutes before turning off for 5 to 15 minutes, depending on the home’s size, the weather, and the unit. There is a problem if the fan turns off and on again after a few minutes. It is also problematic if the unit runs for less than 15 minutes every time it turns on. It may be that the unit is too large for the home and is short cycling. This problem wastes energy and doesn’t dehumidify a home as expected.

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Cause #3: Broken Thermostat

homeowner adjusting thermostat

The thermostat acts as the air conditioner’s brain. It tells the unit what the goal is and lets the system take a break when it is met. However, a thermostat issue will throw off the entire process. The thermostat may be reading the indoor temperature incorrectly or not at all, making your air conditioner think it hasn’t yet met its goal.

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Cause #4: Problem With The HVAC Air Filter

Air filters catch particles like dirt, dust, and debris so they don’t infiltrate the unit and compromise indoor air quality. Old and dirty air filters don’t let sufficient air through for the system to work properly. This forces the system to run continuously. If the filter looks clean or was recently replaced, it may be possible that you used the wrong filter type for the unit. Incorrect filters may be too restrictive for some units, causing them to struggle and stay on.

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Cause #5: Dirty Or Frozen Air Conditioner Condenser Coils

The condenser coils in air conditioners can fall victim to dirt, dust, and debris build-up, causing your unit to act up. The coils can also freeze because of too much refrigerant, the outdoor temperatures plunging, or because the lines are clogged. Dirty or frozen condenser coils can cause the air conditioner to stay on.

Related Article: 7 Steps On How To Unfreeze Your AC Coils

Cause #6: Too Much Hot Air Getting In

image of person sealing air drafts

An air conditioner will run constantly if your house has various air drafts, allowing too much hot air to enter and cold air to leak out. The system tries to compensate for the loss, which means that the air conditioner may not be the reason for the issue. Seal any tiny cracks, holes, gaps around windows and doors, or a lack of insulation in the attic or throughout the house. 

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Cause #7: Wrong Size Air Conditioning Unit

An air conditioner that’s too small cannot cool a big home sufficiently. Instead, the unit will constantly run as it tries to achieve the set indoor temperature. However, it won’t succeed. Consider this a likely cause if you have a brand-new unit that never turns off. Otherwise, the problem would’ve been noticed sooner.

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Cause #8: Trouble With The HVAC Ductwork

Cooling units that run excessively can be caused by a ductwork problem, especially if you have an older home. The ductwork can break down and deteriorate, cave in, or fall apart as time passes. This results in a clog that significantly restricts the airflow and forces an air conditioner to work harder than necessary. Ductwork that isn’t very old can have issues that result in leaks and let the cold air escape before it reaches the rooms around your home. Moreover, ducts without enough insulation can warm the cold air before it is circulated throughout your home.

Related Article: 10 Reasons Why Your AC Unit Isn’t Blowing Cool Air

Cause #9: Not Enough Air Conditioner Coolant

The refrigerant flows through your air conditioner, reducing the hot air’s temperature. Too much refrigerant can cause a freeze within the system, but insufficient refrigerant will force the unit to work overtime. 

Call A Professional HVAC Contractor

Allowing a unit to overwork will inevitably result in a complete system breakdown. This is more expensive to remedy than the problem that started the issue. In most cases, an experienced HVAC technician can correctly diagnose and repair an air conditioner with a fan that continuously runs.

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Point Bay Fuel is the leading heating and cooling service provider in Ocean County and Monmouth County, New Jersey. Our highly skilled and certified technicians specialize in HVAC replacements, tune-ups, installations, repairs, and more. We are proud to deliver top-quality services to all our clients. 

At Point Bay Fuel, we understand the importance of a comfortable and energy-efficient home. We provide competitive pricing for our services. Our maintenance services are made to improve comfort and lower your energy bills. If you need an HVAC repair or replacement, our knowledgeable technicians can recommend the best and most budget-friendly solution. 

Call Point Bay Fuel to schedule a service appointment with us. We offer free, in-home estimates that can assist you in making informed decisions about your HVAC systems. Trust Point Bay Fuel to provide exceptional heating and cooling services at all times. Call now!

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