Why Won’t My Furnace Turn On? Quick Troubleshooting Tips

Engineer performing maintenance on an industrial electrical panel.

As autumn settles in and temperatures drop, there’s nothing worse than finding out your furnace isn’t working. If your furnace worked fine in the spring but refuses to heat now, don’t panic. Before calling in a professional (and spending money on a service call), try these simple troubleshooting steps first.

Inspect the Circuit Breaker

All heating appliances have an electrical disconnect switch on or near the unit. Sometimes, these switches can accidentally be turned off. Make sure the switch is in the ON position. (Pro tip: If you’ve got little ones around, keep in mind this switch is often within their reach!)

A person resets a circuit breaker switch in a modern electrical fuse box.

Testing the Wires

An electrician carefully installs wiring in a wall during a home renovation project.

Once you have access to the wires, perform a simple test:

  1. Disconnect Wires: Remove the wires from the screws on the switch.
  2. Touch Wires Together: Briefly touch the two wires together.
  3. Listen for the Chime: If you hear the doorbell chime (“dong”) every time you touch the wires together, the exterior button is the problem.

Set Your Thermostat Properly

With the issue identified, the repair is straightforward:

  1. Purchase a Replacement: Visit your local hardware store to find a similar replacement button.
  2. Attach the Wires: Connect the wires to the screws on the new switch.
  3. Install the Switch: Secure the new switch in place on the door frame.
A modern smart thermostat set to 22°C keeps the room perfectly comfortable.

Try Resetting the Thermostat

A man adjusts the digital thermostat on a smart home control panel in a modern kitchen.

If the furnace still won’t start:

  • Lower the thermostat setting to below room temperature.
  • Wait a few minutes.
  • Adjust the setting back above room temperature.
    This may reset the furnace’s controls and get it working again.

When to Call a Professional

Concerned woman on the phone seeks help while adjusting her home boiler.

If none of these steps work, it’s time to call in the experts. While no one likes an unexpected service call, a professional technician can pinpoint the issue and ensure your home is warm and cozy again.


Before you reach for the phone, take a few minutes to run through these simple checks. You might just save yourself time, money, and a chilly evening!