6 Reasons Why Your Furnace Isn’t Turning On

Woman adjusting thermostat in winter coat because she's cold due to the furnace not turning on.

When the weather is frightful, there’s nothing worse than realizing that your furnace isn’t working properly. In the worst possible situation, you might even notice that your heating system refuses to turn on at all.

Now, you might be staring at your thermostat, asking, “Why won’t my furnace turn on?” The truth of the matter is that various problems could be to blame. The good news is that you may only need to make a quick, simple fix. The bad news, however, is that you might need to call your local heating experts for assistance.

Let’s go over some of the top five potential reasons why your furnace isn’t turning on.

How Does a Furnace Work?

Before you can start troubleshooting the problem with your furnace, it’s important to understand how these heating systems work. There are various types of furnaces out there — namely those that run on oil, gas, and electricity. Although these heating systems can have different fuel types, they function in mostly the same way:

How Does a Furnace Work infographic

Wrong Thermostat Setting

Since we’re discussing the potential reasons why your furnace isn’t turning on, it only makes sense to start with the simple, quick fixes first. For example, your thermostat might need new batteries. Check to make sure that your thermostat is turned on and set to “heat.”

Tripped Circuit Breaker

If your furnace won’t start, the circuit breaker controlling your furnace may have tripped. Simply locate your circuit breakers and check to make sure they’re all facing the same way. If the breaker has tripped, put the switch back into the “on” position.

Clogged Air Filter

Did you check your thermostat and circuit breakers but still find yourself asking why won’t the furnace turn on? If so, a clogged or dirty air filter could be to blame.

Most heating experts suggest changing furnace air filters every 90 days. Depending on the type of filter you use, your household size, and various other factors, you might need to replace the filter on a more frequent basis — such as every 30 to 60 days. A dirty air filter can lead to many problems, like poor indoor air quality, higher energy bills, and a malfunctioning furnace.

It’s a good idea to check the furnace filter to ensure it isn’t dirty or clogged. If it’s been a while since you replaced the filter, you’ll probably want to consider doing so as soon as possible.

Gas Line Problems

The problems you encounter can vary depending on the kind of furnace you have. For instance, if you have a gas furnace, a closed gas line could be one of the reasons why your furnace isn’t turning on.

To check for this problem, you’ll first need to locate the gas shut-off valve located outside of your house. The valve can be installed in various places, but it shouldn’t be too far from where the furnace is located. If the valve is closed, return it to the “open” position.

Dirty Flame Sensor

Another problem gas furnaces can experience is a dirty flame sensor. This sensor is an important safety feature that automatically shuts off the gas when it can’t detect a burning pilot light. Of course, if the sensor is caked in dirt and grime, it can’t tell whether or not there is a flame. As a result, it will close the gas valve to prevent gas from seeping into your home. 

If you find that your furnace is struggling to keep your home warm, a flame sensor problem could be the culprit. There are many possible reasons why your furnace isn’t turning on, but certainly don’t overlook this one if you have a gas furnace. Also, don’t try to clean the flame sensor yourself. This is a task that should be left to a professional. 

Malfunctioning Blower Motor

We’ve already discussed many potential reasons why your heating system won’t start. However, the problem may persist. Are you still wondering why your furnace won’t turn on? This frustrating issue could be due to a faulty blower motor.

The blower motor is an important component, as it’s responsible for collecting the cold air inside your home, pushing it through the air ducts, and directing it toward the heat exchanger. The heat exchanger, then, heats the air.

If the blower motor malfunctions, there will be no air blowing over the heat exchanger. As a result, you won’t receive any of the warm, comfortable air you were hoping for. The best solution is to schedule a professional furnace service in McKinney, TX.

When You Have Furnace Problems, Call Adon Complete!

“Why won’t my furnace turn on?” If you ask three heating experts this question, you’ll probably receive three different answers. There are many conceivable reasons why your heating system is malfunctioning, and the only way to solve it is to contact a trusted team of professionals. Fortunately, this is where Adon Complete comes in.

As a reputable heating company, we can assist with all of your furnace troubleshooting needs. We’re proud to offer McKinney heating services that local homeowners can count on time and again. Contact us today to schedule a furnace repair!

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