How to Solve a Furnace That Won’t Turn On

Whether you’re just starting your furnace, or it’s been running for part of the winter, when it won’t turn on there’s a panic that sets in. You will ask yourself these questions: “How much will the repairs be?” “How cold will it get?” and “Does my furnace need to be replaced?”

Take a deep breath, and remember that you will get through this momentary crisis. Your household will be okay. There are a variety of reasons a furnace won’t start, some of which you can easily solve without an HVAC service call. Consider the following steps to help you find out why your furnace isn’t starting and what you can do to solve them.

Check for Power

One of the first things to do is ensure you have power coming to the furnace. Without power, your inducer fan, circulating fan, and even electric ignitors will all fail to work.

Find your circuit panel and locate the breaker for your furnace. If it’s off, try turning it back on and see if it stays on. A breaker that continually trips indicates something is happening within the system that needs repairing. Do not attempt to force the breaker to stay closed in any way. Doing so increases the risk of significant damage to your furnace and even an electrical fire.

Check Your Thermostat

Next, move on to check your thermostat to make sure it’s working properly. First, check to ensure that it has power. If it’s a battery-operated model, see if the battery indicator is on the display. If the indicator is on, change the batteries. You should plan to change your batteries every six months. This ensures the thermostat has plenty of power to send the appropriate signals to start up and shut down your system.

Next, check the settings on the thermostat. Make sure it’s set to “Heat,” especially if you’ve recently changed your batteries. Double-check that the time and day settings are correct. Otherwise, programs may not run when you need them to. Finally, check that the fan is set to “Auto.” Setting it to the “On” setting will keep the fan running constantly, making it feel like it’s not igniting the burner to produce heat.

Check Your Furnace Filter

Next, check your furnace filter to ensure that it’s clean. A clogged air filter prevents air from flowing and quickly increasing the heat inside the furnace. This will trip safety sensors to prevent overheating. It will also prevent any damage to the heat exchanger.

Ideally, check your furnace filter every month for dust accumulation, and replace it as soon as possible. The filter size and your air quality will determine how often it needs replacing. This can range from as often as monthly to if only a few times a year.

Consider Your Ignition

If your ignition isn’t working properly, the burner may not light as it should. Older models have a standing pilot light, which has a constant small flame to light the burner. This pilot light can get blown out under certain circumstances and need relighting.

Most modern furnaces have either an intermittent pilot light or a hot surface igniter. The intermittent pilot light uses an electrically generated spark to light the pilot, which then lights the burner. A hot surface igniter is either a silicon carbide or a silicon nitride and uses electricity to make it warm enough to light the burner.

Problems with electric igniters include problems with electrical wiring or failure to get electricity to the furnace itself. Regardless of the problem, it’s best left to a professional to ensure you don’t damage the replacement part or cause secondary damage, both of which can become costly.

Other Mechanical Problems

There are a host of mechanical problems that may result in the furnace failing to start. It’s best to have a professional troubleshoot the issue if the simple fixes don’t work. This way, you’re not guessing what may be wrong. The other problems you may face include:

  • Failing draft fan
  • Faulty ignition switch
  • Failing circulating fan
  • Faulty safety sensors

Contact the Pros in Richmond

Residents around Richmond have relied on our technicians to keep their homes comfortable since 2012. We provide AC and heating installation, repair, and maintenance together with indoor air quality solutions. Call Affordable Service Solutions Heating & Air Conditioning to schedule your furnace service appointment with friendly technicians that you can trust.

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