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First Choice Heating & Cooling Blog

Why Your AC Won’t Shut Off

air-conditioner-plastic-grillWhen it’s hot, you want your air conditioning system to run for as long as necessary to get your house cool. There is such a thing as too long, however! Air conditioners are designed to run in cycles where the compressor comes on for 15–20 minutes and then cycles down until the thermostat registers the need for more cooling. If you start to notice that your AC never seems to cycle down or the fan runs continuously, you may need to have air conditioning repair in Brighton, MI

Yes, this is a serious problem

If you think an AC that just keeps blowing out cool air during the worst heat of summer sounds fine … it’s not. You want your house to be cool, but you don’t want it too cool—and that’s what you’ll eventually get if the compressor doesn’t cycle off. A nonstop AC is also a tremendous money-waster that will send electrical bills through the roof. Worst of all, the massive unrelieved strain placed on the air conditioner’s parts, in particular the compressor and the blower motor, will lead to extra repair problems and an early replacement for the system.

What can cause a runaway AC

Here are the most common causes of an AC running too long:

  • Stuck motor relay: This is an electrical problem with the compressor or blower motor. The relay is what permits electrical current to flow to the motor. If it gets stuck, it will allow current to continue to flow to the motor and won’t turn off until the power is cut off at the circuit breaker. This is the most frequent source of an AC that truly won’t turn off at all.
  • Thermostat problems: Since the thermostat controls when the AC turns on and off, it’s often the cause of an air conditioner that isn’t doing one or the other correctly. The thermostat might read indoor temperatures as hotter than they are, forcing it to keep the AC running longer than necessary. The thermostat may also lose the connection to the AC that signals when to shut off either the blower or the compressor—maybe both.
  • Leaking refrigerant: A nonstop AC is often an early warning that the system is losing refrigerant to leaks. As refrigerant escapes, the air conditioner will lose its cooling capacity and need to stay on longer to cool the house. If the leaks aren’t repaired, the AC’s compressor will eventually burn out, so this is definitely something you want to be fixed ASAP.
  • Dirty condenser coil: The outdoor coil in the condenser cabinet can pick up dust and grime over the season. This makes it harder for the AC to release heat outdoors, causing the AC to have to run for longer because of the trapped heat. Regular maintenance in spring is the best way to avoid a dirty condenser coil. If you have this problem at the end of the summer, call us to chemically clean off the coil. 
  • Undersized AC: Is this a new air conditioner? Then the problem might be that whoever installed it (probably an amateur) put in a unit that is too small for the house. The AC will run overtime because it’s trying to reach a low temperature it can’t reach. The only way to fix this is to replace the unit.

First Choice Heating & Cooling serves Fenton, Linden, Holly, and the surrounding areas. If your home had a voice … it would call First Choice.

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