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Serving The Fresno & Madera Area

70th Anniversary of Purl's Sheet Metal & Air Conditioning

Serving The Fresno & Madera Area


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Purl's Sheet Metal & Air Conditioning Blog

When an AC Runs for Too Long


We’ve written before about the problem of a short-cycling air conditioner, which is when an AC stops its cooling cycle (which usually lasts 15–20 minutes) earlier than normal, then continues to turn on and off rapidly. This is a serious problem that often requires calling for repairs.

There is the opposite version of this problem—an air conditioner that runs for far too long. When an air conditioner spends more than 30 minutes on its cooling cycle, or won’t stop cooling at all, it’s a huge waste of energy and will make the house too cold.

There are several reasons you may start to see this “nonstop AC” problem in your home. You can count on our technicians to find out the exact problem and have it fixed.

Faulty thermostat

If the thermostat in your house is miscalibrated, it may sense that the house interior is hotter than it is. The thermostat won’t register that the AC has reached its target temperature and instead allow the system to run longer.

If your air conditioner won’t shut off at all, the problem may be that the thermostat has lost its connection to the AC that it uses to shut the system down. You can have our technician recalibrate, repair, or replace the thermostat to fix these problems.

Stuck relay

The relay is a switch that controls the flow of electricity to the air conditioner. When the relay is closed, electrical power can move through it. When the relay is open, the electrical power is cut off. The relay can become dirty over time and get stuck in the closed position, forcing the air conditioner to continue to run. Technicians can clean the relay to restore its proper function.

Leaking air ducts

Leaks in the ductwork of an HVAC system will allow cool air to escape into closed-off sections of the house. This wastes money—that’s air you’ve already paid to cool—and it will cause the air conditioner to run for longer to make up for that lost cooling. An air conditioner that’s running too long may be warning you it needs its ducts repaired. We offer air conditioning duct sealing to solve this issue.

Low refrigerant

If an air conditioner loses its refrigerant to leaks, it won’t be able to draw enough heat from the indoor air to cool the house, leading to the AC running for longer and longer periods. Refrigerant leaks pose a danger to the entire air conditioner and will eventually cause the compressor to burn out. If our technicians discover your AC has refrigerant leaks, we can seal them and then restore the lost amount of refrigerant.

Undersized air conditioner

If you have a new air conditioner that has always run for too long, then the AC may be too small for the house. Because the air conditioner isn’t powerful enough to cool the whole house, it will run continuously trying to achieve the impossible. Amateurs often make the mistake of installing undersized air conditioners, which is one of the many reasons to only trust experienced professionals with this job. If you have an undersized air conditioner, the only remedy is to have it replaced.

Contact Purl’s Sheet Metal & Air Conditioning for all your AC needs in the Central Valley. Uncompromised Quality & Customer Service Since 1952.

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