furnace repair

What to do When Your Furnace Wont Turn On

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

You may be able to bypass a furnace repair call with our DIY troubleshooting guide. You don’t need any mechanical skills. And many of these fixes are quick and affordable (or even free).

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

When you require a pro in Chadron, MPC Heating & Cooling can lend a hand.

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

Furnace breakdowns are often caused by forgotten routine maintenance. These evaluations often highlight a costly problem before it begins—and causes your HVAC system to stop working.

During this service, our NATE-certified professionals will closely inspect your furnace, make sure it’s functioning 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 begin troubleshooting your furnace? Follow our step-by-step guide below.

Steps for Troubleshooting Your Furnace

Inspect Your Thermostat

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

If you have a digital thermostat:

  • Switch out the batteries if the screen is blank. If the digital screen is scrambled, you may need a different thermostat.
  • Check that that the switch is set to “heat” instead of “off” or “cool.”
  • Look to see if the program is showing the current day and time and is set to “run.” If you can’t change the program, set the temperature with the up/down arrows and press the “hold” button. This will force the furnace to switch on if thermostat programming is causing complications.
  • Set the temp to 5 degrees warmer than the room’s temperature.
Digital Thermostat

Your furnace should start fairly quickly. If it doesn’t, make sure it has power by pushing the fan switch from “auto” to “on.” If the fan doesn’t start right away, your furnace may not have power.

If you’re using a Wi-Fi thermostat—like one made by Nest, Ecobee, Lux, Honeywell or Bosch—refer to the manufacturer’s website for advice. If you can’t get your smart thermostat to turn on, call us at 308-832-4321 for assistance.

Smart Thermostat

Check Breakers and Switches

If you’ve already checked your thermostat, you will have to make sure your breakers and furnace switch are on.

  • Go 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 handling the panel or breakers.
  • Find the breaker labeled “furnace” or “heat” and confirm that it’s switched in the “on” position. If the breaker has tripped, it will be in the midpoint or “off” position.
  • With one hand, firmly shift the breaker to the “on” position. If the breaker trips and pops back to “off” after you do this, leave it alone. Contact a technician from MPC Heating & Cooling at 308-832-4321 as soon as possible.

Your furnace has at least one wall switch located on or near it—no matter when it was made or who manufactured it.

  • This switch should be flipped up in the “on” position. It can take your furnace up to five minutes to kick on 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, closed off air filters often create issues that are easily avoidable.

  • Your furnace can overheat and stop working too soon, due to dust in the filter diminishing airflow.
  • Your energy bills could increase, because your furnace is turning on more often.
  • Your furnace may not last as long, because it has to work harder.
  • Your furnace could lose power, because an extra dirty filter can cause the breaker to trip.

You can locate 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:

  • Shut off your furnace completely.
  • Grab the filter, hold it up to the light and look through it. Replace it if you can’t see light through it.
  • Install the new filter with the arrow pointing toward the furnace to avoid hurting your machine.

To make the process simpler next time, use a permanent marker on your furnace housing or ductwork to indicate the airflow direction and filter size.

We suggest replacing flat filters once a month. Pleated filters typically last about three months. You can also get a washable filter that will be good for about 10 years.

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

Inspect Your Condensate Pan

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

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

  • If your pan has a PVC pipe/drain: Check that it’s not blocked. 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: Take a look at the float switch. If the switch is “up” and there’s water in the pan, call us at 308-832-4321. You will likely need an updated pump.

Check Inside Your Furnace

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

Contact us at 308-832-4321 if you see anything other than a solid, colored light or blinking green light. Your furnace could be giving an error code that requires professional help.

Clean Your Flame Sensor

Is your furnace attempting to start but turning off without producing heat? A dirty flame sensor could be to blame. When this occurs, 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 alright opening up your furnace. We can also do it for you.

Ready to tackle 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 turn off the power. Shut off the gas as well if your gas valve is not electric.
  • Take off your furnace’s front panel and track 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 normally. If it doesn’t kick on, the sensor might need to be switched out for a new one. Or something else could be wrong. Call us at 308-832-4321 for guidance if this happens.

Relight the Pilot Light

If your furnace is an older style, its pilot light could be out. Relight it following the instructions on the label. You can find 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.
  • Switch the knob to “pilot.”
  • Hold down the “reset” button as you deliver the flame of a long lighter to the pilot light opening.
  • Let go of the “reset” button once the pilot light is lit.

Call us at 308-832-4321 if you’ve followed the steps twice and the pilot won’t light or stay lit.

Check Your Fuel Source

Are other gas appliances operating? 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 turn on?

Call us today at 308-832-4321 or use our online scheduler. We’ll come out to your home and identify what’s wrong.

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