woman looking at thermostat on wall

Here’s Why Your Furnace Keeps Shutting Off Every Few Minutes

Does your furnace refuse to run longer than just a few minutes? At first, this might not seem like a problem. After all, the furnace is running, and warm air is coming out. However, this short-cycling (frequent, short cycles of heat) can point to a problem with your heating system and cause other issues, like uneven heating and high energy bills.

Below, we’ll explain some of the most common reasons why furnaces short-cycle.

1. Oversized Equipment

If your furnace is “too big” for your home, it may shut off before it has a chance to warm your home evenly. What ends up happening is that the thermostat will pick up on a “pocket” of heat around it and think that the rest of your house is that same, cozy temperature. The thermostat will then tell your furnace to shut off.

2. Thermostat in Bad Location

As mentioned above, thermostats can’t tell what the temperature is in all areas of your home. They can only detect the temperature immediately around them. If your thermostat is located right next to a vent or close to an appliance that releases heat, it may think your home is warmer than it really is and turn off your furnace. An HVAC technician can help you move your thermostat to an ideal location.

3. Overheating Equipment

Your furnace might be shutting itself off as a safety measure. Many newer furnaces will turn off automatically when internal components get too hot. This overheating can be caused by problems such as:

  • A dirty air filter that needs to be cleaned or replaced
  • Dust-clogged interior vents
  • Something blocking the roof exhaust vent

4. Failing Flame Sensor

If your furnace is shutting off almost immediately, you can just about guarantee that the problem is a deteriorating flame sensor. The flame sensor is a safety feature in contemporary furnaces. If it doesn’t detect a flame in your furnace, it shuts off the flow of natural gas to the equipment. That way, you don’t have a ton of flammable gas accumulating in an enclosed space or entering your home.

Over time, the condensation and soot made during the heating process can corrode the flame sensor. When that corrosion buildup gets bad enough, the flame sensor has a harder and harder time detecting a flame, so it can start to shut off gas to your furnace prematurely. You can solve this problem by having an HVAC technician replace the flame sensor in your unit.

5. Blocked Room Vents

At some point, you’ve probably been told that you can save money by closing air vents in rooms that no one is occupying. Unfortunately, this practice can have some harmful consequences.

When too many vents are blocked, heat can build up inside your furnace and cause it to overheat after several minutes and shut down. Additionally, the buildup of air pressure in your ductwork can create leaks that make your HVAC system less efficient year-round.

Make sure all of your home’s air vents on the walls, floor, and ceiling are open and that no furniture, rugs, or curtains are blocking them.

6. Blocked Exhaust Vent

Your furnace creates some harmful flue gases as a byproduct of the heating process. One example is carbon monoxide. These flue gases exit your home and get dispersed outdoors via the exhaust vent.

Occasionally, leaves, twigs, bird’s nests, or animal carcasses can block this vent. Not only can this issue lead to short cycling, but it can also create a safety hazard. Don’t wait to involve a professional to clear the blockage so that toxic flue gases can leave your system safely once again.

Heating Repairs Throughout the Atlanta Metro Area

Are you having trouble with a furnace that just won’t cooperate? Don’t hesitate to contact Premier Indoor Comfort Systems, LLC for a reliable repair: (770) 749-7667.

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