Is Your Furnace Turning on and off Rapidly?

5 Things You Can Troubleshoot Before Calling for Help

No one wants their furnace to have problems during the winter. So if you notice that your furnace is turning on and off in rapid succession, here are some things you can check before you suffer too long or call a technician out.

What Is Short-Cycling?

The problem of a furnace turning itself off and on rapidly is known as short-cycling. And these cycles should be really short, such as only one or two minutes of functioning. Normally functioning furnaces can turn on for several minutes and then turn off even as part of regular activity.

The good news is that short-cycling probably means that your furnace’s safety systems are working well. Why? The unit is designed to prevent overheating by turning itself off rather than becoming dangerous, and it’s doing just that. The trick is to find out where in the system the error is occurring.

What Can You Check?

Short-cycling can be caused by several different problems. Here are five problems you can troubleshoot yourself with little or no risk.

First, start with the thermostat. Check the batteries, if applicable. Also, if you haven’t used the furnace much during the fall or early winter, the programming may be leftover from last spring or may have become corrupted during the summer. If possible, turn off the automatic settings and turn on the furnace manually. If it stays on this time, create a new setting program. If the thermostat is near drafts, outside walls, or by windows, that could also make the system unable to correctly register the right temperature in the house.

Second, look at your filters. Clogged air filters can form enough buildup that air cannot properly flow over them and circulate to the heat exchangers. This lack of air circulation leads to overheating, which is why your furnace may be shutting off quickly. Turn the furnace off and replace the air filters with proper ones as recommended by your furnace servicing company or the manufacturers.

Third, feel the flow. The blowers are the part of the heating system that circulates warm air out the vents and into your home. You can tell if the blowers are functioning well by holding a hand over the vents when it does come on. If you aren’t getting any significant hot air, the motor is likely the problem.

Fourth, check the flue. If you have a rooftop flue and are comfortable getting on the roof, see if hot gas is venting out of the pipe. Be careful not to touch it, though, as it’s very hot. If the gases aren’t venting properly and you can see inside, you may find that it’s blocked by debris or an unfortunate, deceased rodent.

Finally, consider changes you’ve made to the house recently. If you used the summer to do some renovations and changed the interior in any significant ways, the furnace may no longer be the right size for the home.

A furnace too large and powerful for the space it’s heating could be having to turn off more quickly than normal to keep the temperature right. In addition to being uncomfortable, this can eventually damage the furnace.

What Should You Do Now?

If you have gone through this list of simple fixes and the problem remains, it could be a deeper issue that most owners can’t fix on their own, such as blower motor or ignition system breakdown. But you will have saved time, comfort, and money by ruling out things you can do on your own.

For help with your furnace, call us anytime at HELP Plumbing, Heating, Cooling and Electric. We provide quick service in Ohio, Kentucky, and Indiana.