furnace repair

What to do When Your Furnace Refuses to Switch On

It might feel overwhelming to troubleshoot your furnace when your heat won’t run. But it doesn’t have to be that way.

You might be able to avoid a furnace repair call with our DIY troubleshooting guide. You don’t need any industry skills. And most of these fixes are brief and inexpensive (or even free).

This checklist will walk you through how to fix your furnace when it won’t start, won’t stay on or won’t light.

When you need a pro in Winnipeg, Kirkfield Heating & Air Conditioning can be there.

We service most makes and models of furnaces. If you need a new heating system, we also offer furnace replacement and furnace installation.

Furnace breakdowns are generally caused by forgotten routine maintenance. These checkups often reveal an expensive problem before it gets worse—and causes your HVAC system to break down.

During this service, our NATE-certified professionals will thoroughly inspect your furnace, make sure it’s operating properly and lubricate moving parts. A well-kept furnace often lasts longer and operates more efficiently, saving you more on your heating bill.

Ready to start troubleshooting your furnace? Follow our step-by-step guide below.

Steps for Troubleshooting Your Furnace

Take a Look at Your Thermostat

Start by examining your thermostat. Is it telling your furnace to turn on?

If you have a digital thermostat:

  • Replace the batteries if the screen is unresponsive. If the digital screen is scrambled, you may need to replace your thermostat.
  • Check that that the switch is set to “heat” instead of “off” or “cool.”
  • Look to see if the program is showing the correct day and time and is set to “run.” If you can’t change the program, fix the temperature by pushing the up/down arrows and press the “hold” button. This will force the furnace to start if thermostat programming is causing a problem.
  • Set the temperature to 5 degrees warmer than the room’s temperature.
Digital Thermostat

Your furnace should kick on shortly. If it doesn’t, double check that it has power by moving the fan switch from “auto” to “on.” If the fan doesn’t run immediately, your furnace may not have access to power.

If you’re utilizing a Wi-Fi thermostat—like one made by Nest, Ecobee, Lux, Honeywell or Bosch—check the manufacturer’s website for advice. If you can’t get your smart thermostat to turn on, call us at 204-272-8128 for support.

Smart Thermostat

Check Breakers and Switches

After that, you will have to make sure your breakers and furnace switch are on.

  • Head to your house’s main electrical panel. It’s the gray metal box on the wall in your basement, garage or closet.
  • Dry off your hands and feet before touching the panel or breakers.
  • Pinpoint the breaker labeled “furnace” or “heat” and double-check that it’s switched in the “on” position. If the breaker has tripped, it will be in the middle or “off” position.
  • With one hand, firmly move the breaker to the “on” position. If the breaker trips and goes back to “off” after you do this, leave it alone. Contact a technician from Kirkfield Heating & Air Conditioning at 204-272-8128 right away.

Your furnace has at least one wall switch located on or near it—no matter its age or brand.

  • This switch should be flipped up in the “on” position. It can take your furnace up to five minutes to get working if the switch was off. (Not sure where your furnace is located? Look in your basement, garage or utility closet. It could also be placed in a crawl space or attic.)

Replace Your Air Filter

Dirty, blocked air filters often generate complications that are easily avoidable.

  • Your furnace can overheat and turn off too soon, due to dust in the filter hampering airflow.
  • Your energy bills could increase, because your furnace is working more often.
  • Your furnace may not last as long, because it has to work harder.
  • Your furnace could lose power, because an excessively dirty filter can cue the breaker to trip.

You can get to your air filter inside your furnace’s blower component, attached filter case or wall-mounted return air grille. Its placement depends upon what type of furnace you have.

Replace furnace filter

When switching out your filter:

  • Turn off your furnace completely.
  • Grab the filter, hold it up to the light and look through it. Get a new filter if you can’t see light through it.
  • Replace the new filter with the arrow pointing toward the furnace to avoid damaging your system.

To make the process easier in the future, use a permanent marker on your furnace housing or ductwork to indicate the airflow direction and filter size.

We suggest replacing flat filters monthly. Pleated filters usually last about three months. You can also get a washable filter that will work for about 10 years.

If you have children or pets, you may need to replace your filter more frequently.

Inspect Your Condensate Pan

Condensate pans, or drain pans, hold water your furnace takes from the air.

Follow these steps if your furnace is seeping water or there’s standing water in the pan.

  • If your pan has a PVC pipe/drain: Be sure that it’s clear. If it’s not, you can use a special pan-cleaning tablet from a home improvement or hardware store.
  • If your pan has a pump: Check out the float switch. If the switch is “up” and there’s water in the pan, call us at 204-272-8128. You will likely need an updated pump.

Check Inside Your Furnace

You can check the status of your furnace’s blower motor by peeking inside the plastic window. Depending on the kind, this light could be somewhere on the outside of your furnace.

Call us at 204-272-8128 if you see anything other than a steady, colored light or blinking green light. Your furnace is probably giving an error code that needs professional assistance.

Clean Your Flame Sensor

Is your furnace attempting to start but shutting off without generating heat? A soiled flame sensor could be be the reason. When this takes place, your furnace will try to start three times. Then, a safety feature will shut it down for about an hour.

You can clean the flame sensor yourself if you feel confident opening up your furnace. We can also do it for you.

Want to take on cleaning the sensor yourself? You’ll need the following:

  • A 1/4” hex screwdriver or wrench
  • Piece of light-grit sandpaper, steel wool or emery cloth
  • A dry, clean paper towel

Next:

  • Use your furnace’s wall switch or breaker to switch off the power. Shut off the gas too if your gas valve is not electric.
  • Open your furnace’s front panel and trace the wire to the flame sensor, which looks like a thin, bent rod.
  • Unscrew the rod and use your sandpaper, steel wool or emery cloth to gently clean the metal rod.
  • Use a paper towel to wipe off the rod.
  • Replace the sensor.
  • Put your furnace’s doors back on.
  • Turn the furnace’s power back on. Your furnace may run through a series of checks before it starts regularly. If it doesn’t start, the sensor might need to be replaced. Or something else could be the problem. Call us at 204-272-8128 for guidance if this happens.

Relight the Pilot Light

If your furnace is an older style, its pilot light could be blown out. Relight it following the instructions on the label. You can read the label on your furnace’s doors.

Or you can follow these steps:

  • Locate the switch on the bottom of your furnace labeled “pilot,” “on” and “off.”
  • Rotate the switch to the “off” position.
  • Wait at least five minutes. This avoids the possibility of starting a fire.
  • Move the knob to “pilot.”
  • Hold down the “reset” button as you bring the flame of a long lighter to the pilot light opening.
  • Release the “reset” button once the pilot light is lit.

Call us at 204-272-8128 if you’ve followed the steps twice and the pilot won’t light or stay lit.

Check Your Fuel Source

Are other gas appliances functioning? If they’re not, your natural gas service could be off. Or you could be out of propane.

We Can Diagnose Furnace Problems

Made it through our troubleshooting guide but your furnace still won’t work?

Call us today at 204-272-8128 or use our online scheduler. We’ll come out to your home and find out what’s wrong.

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