My Furnace Keeps Shutting Off Early—What’s Wrong?

Right at a time when Florida has gotten fantastically cold winter weather and you need your home’s furnace more than ever, it starts shutting down early on you. What’s happening and how can you stop it?

The simple answer is that your furnace is short cycling and you’ll probably need to call our experts for furnace repair in Wesley Chapel, FL to make it work right again. 

There’s a longer answer as well, and if you want the lowdown on your furnace slowdown, follow up below.

The Furnace’s Heating Cycle

The heating cycle of a furnace goes through several stages:

  • First, gas starts to flow to the burners.
  • Next, the electronic ignition system ignites the burners.
  • When the furnace limit switch detects that the interior of the furnace has heated up enough, it activates the blower fan.
  • The fan pushes air through the furnace, where it warms up, and then moves into the ventilation system to the rest of the house.
  • When the thermostat registers the house has warmed up to the target temperature, it signals to shut off the burners.
  • When the furnace cools down enough, the limit switch then turns off the blower fan. 

This complete cycle, on average, lasts from 10-15 minutes. On colder days, you may expect it to last for longer, but not much longer. The time between cycles will shorten, but you can expect the furnace to go through 3-5 cycles an hour.

Short Cycling

A furnace is short cycling if its cycle time drops below 10 minutes. When this happens, the furnace will go through a rapid start-and-stop process where it can cycle 8-10 times per hour. 

Short cycling is a symptom of a range of different malfunctions, but it’s also damaging on its own. The constant start-stop places excessive wear and tear on the furnace components. This will cause extra repairs and likely cut down the furnace’s service life—maybe by several years if the short cycling is allowed to continue.

All that extra strain also means the furnace drains more power, resulting in larger heating bills. Finally, the short heating cycles don’t allow the furnace enough time to generate the heat a house needs, creating uneven comfort and cold spots. 

The Causes of Short Cycling

There are numerous reasons why a furnace can start to short cycle and this is why it’s important to always call on HVAC professionals to look into the problem. Experts know how to diagnose short cycling so they can make the correct call on solutions.

The problem might be a simple case of a clogged air filter so check to see if you need to put in a new filter before calling us for help. Other issues that can cause short cycling include a faulty limit switch, an overheated heat exchanger, a malfunctioning blower motor, gas flow obstructions, dirty burners, and a miscalibrated thermostat. The worst-case scenario is that the furnace is too old to do its job anymore. This is often the case with a furnace that is more than 15 years old. 

You can trust our team for honest answers about your furnace’s troubles and the best solutions. 

Contact us today and “Experience the Balanced Air difference!”

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