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What to Know Before Installing a Furnace

Is it a Problem if My Furnace Repeatedly Stops and Starts?

Why Does My Furnace Start Then Stop and Start Again?

Are you experiencing an issue with your furnace where it stops and starts again – repeatedly? You may not have to worry as most heating and furnace systems don’t run constantly but rather cycle on and off about 3-8 times an hour.

However, if you are hearing your furnace start up and shut off much more often, more like every other minute or so, then that sounds like there’s a bit of trouble. This type of furnace problem is called “short cycling” and is among one of the more common problems seen with furnaces. Depending upon the cause, this can either be a simple fix that a capable homeowner can perform, or it may be something that an experienced HVAC expert will have to fix.

In this article, we’re going to take a look at what short cycling is and what some of the common causes for why a furnace stops and starts again.

What Is Short Cycling?

No, it is not going for a quick bike ride. Short cycling can refer to two things:

1.) Your furnace’s heating cycles are reaching short of the thermostat’s set temperature,

2.) Or they running more frequently and for shorter periods.

Oftentimes, the latter happens during the winter months when you need the furnace the most. Either way, your house is most likely not reaching the temperature that you desire.

One good thing about short cycling is that means that your furnace’s safety features are working. This is essentially a “cry for help” from your furnace that needs some maintenance done. I think that we can all agree that it’s much better for your furnace to short cycle than for your home to start on fire!

Now that we know what short cycling is, we can move on to reasons why your furnace might be short cycling.

Reasons For A Furnace To Short Cycle

Here are the four most common reasons why a furnace might short cycle.

Furnace Filter Installation/Replacement

1. You Have a Clogged Air Filter

If your air filter is clogged with dust and dirt, the airflow to the heat exchanger becomes restricted, and the component overheats. This, in turn, triggers the high limit switch or also known as the safety shutoff.

A simple fix to this problem is to turn off the furnace altogether and change the filter (if you have a disposable type of filter). Permanent filters, which do a better job of protecting your furnace, have the benefit of being more eco-friendly as they are designed to be cleaned and reused.

Whichever filter you use, be sure to inspect it monthly and change or clean it every 90 days. For even better airflow, open some of your vents and have your furnace blower wheel cleaned.

2. Your Thermostat Is The Problem

Check your thermostat to determine if it is turned on. Make sure it’s switched to “HEAT” and set at the correct temperature. If the temperature setting is too low, your furnace will shut off more frequently.

Consider thermostat location as well. The thermostat should be positioned away from sources of heat or cold and mounted about 1.5 meters above floor level. Ensure that it isn’t mounted too high because, as you may remember from science class, hot air rises. If the thermostat registers extreme temperatures, a shortened furnace cycle may result.

Another possible problem could be that the thermostat is malfunctioning and not sending a signal to your furnace. Check this out with a person who lives with you. One person should stand next to the thermostat, and the other next to the furnace. Slowly raise the thermostat setting and listen for noise from the furnace. The lack of any sound indicates that you may need professional thermostat repair or replacement.

Read More: Signs Your Furnace Needs a Replacement

Heating and Cooling Guide - Step 1

3. You Have A Dirty Flame Sensor

The gas furnace’s flame sensor is a safety device that cuts off the supply of natural gas when no flame is detected. If your flame sensor develops soot or corrosion, it can’t function properly and will keep turning off the gas valve.

If you suspect that you have the problem of a dirty flame sensor, be sure to get an expert furnace repair as soon as possible.

4. The Furnace Is Too Big For Your Home

The fourth and final reason you should consider is that your furnace may simply be too large for the size of your home. An oversized furnace will heat the space too quickly, shut off, and abruptly start again when the house cools down.

This stopping and starting are not only annoying, but it also wastes energy and wears your furnace out faster than usual. Furthermore, your home is never really a consistent, comfortable temperature.

The best solution is to replace your furnace with a correctly-sized, energy-efficient model, especially if it’s over 15 years old.

Read More: What to Know Before Installing a New Furnace

Is It A Problem If My Furnace Repeatedly Stops And Starts?: In Conclusion

Now that you know about some of the more common problems that can cause your furnace to stop and start again, you’ll be able to better evaluate the situation. Some of these problems are something that an experienced or adventurous homeowner can fix, but others are something that will require a experienced HVAC expert to remedy.

Whatever your furnace problem, you can always rely on Modern HVAC for help. Our professional furnace repair or replacement specialists can help you determine what the root cause of your furnace issues are, give you a rundown of the furnace installation process, and how to properly maintain your furnace. We are the heating and cooling experts you can rely on in Appleton, the Fox Valley, and beyond!

Modern Sheet Metal provides furnace and air conditioner service, repair, replacement and installation throughout Appleton, Neenah, Menasha, Darboy, Kimberly, Kaukauna and Greenville. Please call us at 920-733-4713 to discuss your residential or commercial heating & cooling needs!