When your furnace won’t start, doing your own furnace repair in Tucker, Georgia, can feel pretty overwhelming.

Fixing your furnace might feel like a complicated process when your heat won’t start. But it doesn’t have to be like that.

There are a few quick, reasonable fixes you can do yourself to skip a furnace repair call.

If your furnace won’t turn on, won’t stay on or won’t ignite, try the troubleshooting list below before calling an HVAC professional.

If you find you need help from a heating and cooling professional and live in Tucker, ACS Heating and Air Conditioning can provide assistance to you. We can repair most brands of heating systems and also provide emergency furnace repair.

If it’s time for a new heating system, we also offer furnace installation.

While you’re talking with us, think about a regular furnace maintenance plan that might help you avoid repairs in the future. We can tell you how frequently your furnace should be inspected by one of our certified professionals.

Go through our easy guide below to start troubleshooting your furnace. Most of these steps don’t require mechanical expertise.

Furnace Repair Checklist

1. Check the Thermostat

To start, make sure your thermostat is telling your furnace to start.

Digital Thermostat

Replace the batteries if the screen is blank. If the digital screen is jumbled, the thermostat may need to be replaced.

Make sure the switch is set to “heat” instead of “off” or “cool.”

Ensure the program is set to the correct day and time and is set to “run.” If you’re having problems overriding the program, set the temperature by using the up/down arrows and press the “hold” button. This will make the furnace to start if thermostat programming is causing trouble.

Increase the temperature setting to 5 degrees warmer than the room temperature.

If your furnace hasn’t kicked on within few minutes, make sure it has power by toggling the fan switch from “auto” to “on.” If the fan doesn’t run, your furnace might not have power.

Smart Thermostat

If you have a smart thermostat—like one made by Nest, Ecobee, Lux, Honeywell or Bosch—troubleshooting is very model-specific. Refer to the manufacturer’s website for help. If you still can’t get your Wi-Fi thermostat to work, call us at 770-450-1539 for heating and cooling service.

2. Examine Breakers and Switches

Next, you will need to check if your breaker and furnace switch are on.

Look for your house’s main electrical panel. If you aren’t sure where it is, search for a gray metal box in your basement, garage or closet.

Make sure your hands and feet are dry before touching the panel or breakers.

Locate the breaker labeled “furnace” or “heat,” and make sure it’s switched “on.” If the breaker has tripped, it will be in the middle or “off” position.

Using one hand, firmly switch the breaker to the “on” position. If the breaker immediately trips and pops back to “off,” leave it alone and call a professional from ACS Heating and Air Conditioning at 770-450-1539 right away.

It doesn’t matter how old your furnace is or what brand it is, it has at least one standard wall switch located on or by it.

Make sure the switch is flipped up in the “on” position. If it was turned off, expect your furnace to take up to five minutes to turn on. (If you don’t know where to find your furnace, check your basement, garage or utility closet. It could also be in a crawl space or attic.)

3. Replace the Air Filter

When it comes to furnace breakdown, a filthy, clogged air filter is often the top culprit.

If your filter is too dirty:

  • Your furnace won’t be able to stay on, or it could overheat from limited airflow.
  • Your energy bills could increase because your furnace is turning on more often.
  • Your furnace could fail prematurely because a dirty filter causes it to work overtime.
  • Your furnace can lose power if an extremely dirty filter causes the breaker to trip.

Depending on what type of furnace you own, your air filter will be inside the blower compartment of your furnace, an attached filter case or wall-mounted return air grille.

To replace your filter:

  1. Turn off your furnace.
  2. Pull out the filter and angle it toward the light. If you can’t see light through it, use a new one.
  3. Insert the new filter with the arrow pointing toward the furnace to avoid damage.

Flat filters should be replaced monthly, while pleated filters should last about three months. You can also buy a washable filter that will last about 10 years. If you have children or pets, you may have to put in a new filter more often.

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

4. Inspect the Condensate Pan

Commonly known as drain pans, condensate pans hold water your furnace removes from the air.

If water is dripping out of your furnace or its pan has standing water in it, follow these steps.

  • If your pan has a drain (look for a PVC pipe), check that it isn’t clogged. If it needs to be drained, use a special pan-cleaning tablet you can buy at home improvement or hardware stores.
  • If your pan contains a pump, check the float switch. If the switch is stuck “up” with standing water in the pan, contact us at 770-450-1539, because you will possibly need a new pump.

5. Check for Furnace Error Codes

If malfunctions persist, peek inside your furnace’s plastic window to confirm the status of the blower motor. Depending on the model, the light could also be attached on the outside of your furnace.

If you see anything except a steady, colored light or blinking green light, call us at 770-450-1539 for HVAC service. Your furnace may be giving an error code that needs professional help.

6. Clean the Flame Sensor

If your furnace tries to start but shuts off without blowing heat, a dirty flame sensor could be to blame. When this happens, your furnace will attempt to turn on three times before a safety feature powers it down for about an hour.

If you feel comfortable with opening up your furnace, cleaning your flame sensor is something you can do yourself. Or, one of our heating service experts can do it for you.

If you want to clean the sensor yourself, you’ll need:

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

Next:

  • Turn off the furnace’s power by using its wall switch or breaker. If your gas valve is not electric, you will need to shut off the gas as well.
  • Lift off the furnace’s front panel and track the wire to the flame sensor.
  • Unscrew the rod and use your sandpaper, steel wool or emery cloth to carefully rub the metal rod.
  • Wipe off the rod with a paper towel.
  • Remount the sensor.
  • Replace the furnace doors.
  • Turn the furnace’s power back on. It may run through a set of checks before resuming regular operation. If your furnace doesn’t ignite, the sensor may need to be replaced or something else might be wrong. If this happens, contact us at 770-450-1539 for heating and cooling repair assistance.

7. Relight the Pilot Light

If you own an older furnace, the pilot light could be turned off. To relight it, find the instructions on a label on your furnace, or follow these steps.

  • Locate the switch on the bottom of your furnace labeled “pilot,” “on” and “off.”
  • Turn the switch to the “off” position.
  • Wait at least five minutes to avoid possibly creating a fire.
  • Turn 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.

If you have followed the instructions twice and the pilot light still won’t light or stay lit, call us at 770-450-1539 for furnace service.

Check Your Fuel Source

Try turning on another gas appliance. If it doesn’t work, your natural gas service could be turned off, or you could be out of propane.

We Can Help with HVAC Repair

Followed our troubleshooting guide but your furnace still won’t work?

Call us today at 770-450-1539 or contact us online. We’ll come out and figure out the problem.

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