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Why Does My AC Keep Turning Off Too Early?

vent-cover-in-ceilingA common cause for an AC failing to keep a house cool enough during summer is because the air conditioning system isn’t completing its full cooling cycle and instead shuts down early. Sometimes the air conditioner may come back on soon after and repeat the process; this is called short-cycling. But the AC may also simply shut off and stay off for a long stretch. Either is bad news for your comfort, since it doesn’t give the cool air ample time to spread through the rooms, and short cycling brings the added problem of extra strain put on the system.

Below we’ll go over some of the more common reasons your AC might be shutting down before it’s done its job.

ONE: Condensate pan overflow

When your AC shuts off suddenly, do you find that the screen on the thermostat has gone blank? If this is the case, then what’s likely happened is an overflowing condensate pan has triggered the AC’s limit switch and turned the system off. This is probably due to a clogged condensate drain or broken condensate pump, and in either case, you’ll need professionals to fix the problem.

TWO: Miscalibrated thermostat

The thermostat may be the source of the AC turning off when the house is still warm. Thermostats have sensors they use to register the general temperature of the house, and these sensors can become miscalibrated. If your thermostat senses the house is cooler than it is, it will shut the AC off early. Don’t lower the thermostat more to overcome this: you want the problem fixed, and technicians can take care of recalibrating the thermostat.

THREE: Clogged air filter

So many AC problems can come from a clogged air filter! When this filter is congested, it can lead to problems like a frozen evaporator coil, which in turn will cause the AC to short-cycle and shut down early. 

FOUR: Refrigerant leaks

Leaking refrigerant causes many issues for an air conditioner, eventually leading to compressor burn-out. An AC that short-cycles or shuts down early is often warning of a refrigerant leak, and this is something you’ll want professionals to investigate so it can be repaired if it’s occurring. 

FIVE: Oversized AC

Is this a new AC for your house? Did an amateur install it? In that case, you probably have an air conditioner that was incorrectly sized when installed. If an AC is too powerful (oversized) for the house, it will shut down early because it will lower the temperature so fast that the thermostat will register it’s already finished the job and shut it off. The only “repair” for an oversized AC is to replace it—and make sure professionals do the replacement!

SIX: The AC is too old

An air conditioner that’s 15 years older or more will start to encounter problems like early shutdowns. The system is simply too worn to do its old job properly. You can call our technicians for the air conditioning service in Essex, VT that will tell you if repairs are worthwhile or if it’s time to get a new AC.

Red Rock Mechanical, LLC serves Northwest Vermont and Northeast New York. Call us for 24-hour air conditioning service.

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