Furnace Keeps Turning On and Off Repeatedly? | R. A. Styron Heating | Chesapeake Va

If your furnace keeps turning on and off repeatedly, it can be stressful at best, and cold or downright uncomfortable at worst. First, it is important to realize that a furnace which is “short-cycling,” as we call it in the business, probably means that its safety features are working properly, so breathe a sigh of relief.  In fact, in all likelihood, that’s why the furnace keeps turning on and off – it turns on normally, then for some reason, it thinks that an unsafe condition exists, and turns itself off again as a safety precaution.  But let’s not wait for those safety features to fail too…you definitely want to find the source of the problem.

Furnace Keeps Turning On and Off Repeatedly – But Why?

If your furnace is cutting on for a few seconds to a minute, then turning itself off again just to start the process over again after a few seconds, it’s short-cycling.

All furnaces are meant to cycle on and off frequently. A properly sized furnace should not cycle anymore then three to eight times per hour. This will depend on the outside temperature, size of the furnace relative to your home, and various other factors. Even if your furnace is cycling more then you fell necessary, this doesn’t necessarily mean that it is short-cycling. It could just be a drop in the temperature.

The frequency with which your furnace cuts on and off is not quite as concerning as how long the furnace runs when it does turn on.

A short-cycling furnace will usually only for for minute (maybe two) before shutting off again. A properly functioning furnace will cut on and run for several minutes before shutting off again. So, before calling out a professional, make sure you pay attention to how long it runs first.

Once you have determined that the furnace is definitely short cycling there are a few things that you can do as the homeowner to solve the issues before calling in the experts.

Is your furnace filter dirty? If so, change it.

Left: New Filter Right: Three Month Old Filter

First things, first. Check your furnace air filter. Your filter should be changed every 30-90 days. Most people think that the filter is just put in place to help keep your indoor air clean, but this is just not the case. The filters are in place to not only help indoor air quality but they also shield your furnace from dust and dirt. Dirt build up will eventually cut off air flow to your furnaces internal parts causing them to over heat. This will lead to the safety features we talked about earlier to engage cutting the furnace off before more damage is caused.

Placement of the air filter will depend on the type of system you have in your home. They are always located new the blower house. Listen for the fan when your furnace kicks on, find the sound and you’ve found the filter location. Most filters are relatively easy to find.

So, before doing anything else, check your filter. They are relatively cheap and easy to replace. If you need help deciding on which filter to choose when purchasing your new one click here.

Do you have a bad thermostat?

Like most electronics in our life, thermostats do and will go bad after time. If you know how to test your thermostat, go for it. If not it’s an easy diagnosis and fix for any professional at a relatively low cost to you.

If you know that you are looking into replacing your old thermostat with something new, we have the information you seek. You can check out our blog on thermostat options here. Rather you are planning on replacing it yourself or are calling on the professional, know what your needs are and what options you have for them.

When all else fails…

Call in the professional. Remember those safety components we discussed earlier? If you’ve gotten to this point in our blog, chances are you have a fault safety switch or flame sensor. Having a bad flame sensor or limit switch will lead to the furnace short-cycling, as well. These are put into place to prevent damage to the system and your home and should be not taken lightly. Our well seasoned team of professionals can not only diagnosis any problem you’re having with your furnace, they can repair it efficiently and properly as well. Give us a call and schedule your service appointment today.



Leave a Comment