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Short-Cycling: Why It Happens to an Air Conditioner

Evaporator Coil

I have a nice pattern for my life. It’s a bit mellower than for humans, but it keeps me busy. I nap on the couch when the sunlight hits it, I go on regular walks, I have my dinner, and I’ve got my regular blogging duties.

I bring this up because I want to talk to you about what happens when a routine gets interrupted. Not your routine. Your air conditioner’s routine. During the summer, when you have the AC running, it should work in familiar patterns: turning on, running for a stretch, then turning off for another stretch before starting up again. If you keep the thermostat setting steady during the day (which I recommend), these on-and-off patterns should stay about the same. This is called the cycle of the air conditioner.

But when you notice the AC is starting and stopping far more often than normal, you may have a problem called short cycling. Sorry to say, but this isn’t good!

Why is this a problem?

It means your air conditioning system is shutting off its cooling cycle too early—before it reaches the setting on the thermostat. It will then come back on a short time later, then shut off again. And this …

  • … keeps your house from getting fully cool …
  • … puts extra strain on the AC, wearing it down faster …
  • … and raises your bills.

Why is it happening?

This is the tricky part because there are many possible causes for it. This is why I advise you call us for AC repair in Loudon, TN when this starts to occur. It may be a small problem. It could be a gargantuan one.

  • The AC is the wrong size: I’ll start with the gargantuan one. If you had your air conditioner installed by an inexperienced and unlicensed technician (ol’ “Chuck in Truck” I’ve talked about before), the AC may be too large for the house. It blasts out too much cool air at once and thinks it’s done the job, then shuts down. The only way to fix this is to have our trained people put in a new AC—one that’s the correct size. We take the load calculation to size an air conditioner very seriously!
  • A clogged air filter: Here’s a simpler problem. You’ve left the air filter in the HVAC cabinet for too long. The strain this clogged filter puts on the blower motor can trigger short-cycling.
  • Leaking refrigerant: If the AC is losing its precious refrigerant to leaks, it throws the entire operation of the system out of whack. The AC will overheat, causing it to shut down early. This must be fixed ASAP because it will eventually cause the air conditioner to completely break down.
  • Frozen evaporator coils: Is there ice on the indoor evaporator coil? It shouldn’t be there! The ice stops the AC from pulling enough heat from your house and also leads to early shutdowns. Please call us to find out why the coil is frozen, and don’t try to scrape the ice off on your own.

Stay cool and may your cycles never be short!