furnace repair

Chatsworth is Getting Cold, but My Furnace Wont Turn On

It might feel scary 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 technical skills. And the majority of these fixes are fast and low-cost (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 require a pro in Chatsworth, True Temp Heating & Air Inc can be there.

We repair and maintain most makes and models of furnaces. If you need a more modern heating system, we also offer furnace replacement and furnace installation.

Furnace breakdowns are usually caused by a lack of routine maintenance. These evaluations often highlight a costly problem before it gets worse—and causes your HVAC system to stop working.

During your appointment, our NATE-certified professionals will carefully inspect your furnace, make sure it’s operating properly and lubricate moving parts. A well-managed furnace often lasts longer and operates more efficiently, saving you more on your heating costs.

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 looking at your thermostat. Is it telling your furnace to start?

If you have a digital thermostat:

  • Replace the batteries if the screen is off. 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.”
  • Make sure the program is showing the correct day and time and is set to “run.” If you can’t override the program, change the temperature by pushing the up/down arrows and press the “hold” button. This will require the furnace to start if thermostat programming is causing complications.
  • Set the temperature to 5 degrees warmer than the room’s temperature.
Digital Thermostat

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

If you’re connected to a Wi-Fi thermostat—like one made by Nest, Ecobee, Lux, Honeywell or Bosch—check the manufacturer’s website for guidelines. If you can’t get your smart thermostat to work, call us at 706-695-7492 for assistance.

Smart Thermostat

Check Breakers and Switches

Next, you will want 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 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 move the breaker to the “on” position. If the breaker trips and goes back to “off” after you do this, leave it alone. Contact an expert from True Temp Heating & Air Inc at 706-695-7492 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 get working if the switch was off. (Not sure where to find your furnace? 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 generate complications 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 climb, because your furnace is starting up more often.
  • Your furnace may fail permantly faster, because it has to work harder.
  • Your furnace could lose power, because an excessively dirty filter can prompt 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 position depends upon what kind of furnace you have.

Replace furnace filter

When changing out your filter:

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

To make the process simpler 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 each month. 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 change your filter on a more regular basis.

Look at Your Condensate Pan

Condensate pans, or drain pans, catch water your furnace pulls 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: Check out the float switch. If the switch is “up” and there’s water in the pan, call us at 706-695-7492. You will likely need a new pump.

Look Inside Your Furnace

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

Call us at 706-695-7492 if you see anything other than a solid, colored light or blinking green light. Your furnace is likely giving an error code that needs professional service.

Clean Your Flame Sensor

Is your furnace trying to start but turning off without producing heat? A dirty flame sensor could be at fault. When this takes place, your furnace will try to turn on 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.

Want 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 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.
  • Put back 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 start, the sensor might need to be updated. Or something else could be wrong. Call us at 706-695-7492 for assistance if this happens.

Relight the Pilot Light

If your furnace is an older style, its pilot light could be extinguished. 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.
  • Move 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.

Reach out to us at 706-695-7492 if you’ve followed the guide 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 start?

Call us today at 706-695-7492 or use our online scheduler. We’ll come out to your home and identify what’s wrong.

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