furnace repair

Columbia is Getting Cold, but My Furnace Wont Turn On

Troubleshooting your furnace might feel like an overwhelming task when your heat won’t work. But it doesn’t have to be like that.

There are several fast, low-cost fixes you can do on your own 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 contacting an HVAC professional.

If you find you need help from an expert and live in Columbia, Watts Electrical & Air Conditioning can help you. We repair most makes of heating systems.

If you’re ready for a new heating system, we also do furnace replacement in Columbia.

While you’re chatting with us, think about a regular furnace maintenance plan from Watts Electrical & Air Conditioning that may help you avoid problems in the future. We can tell you how often your furnace should be checked by one of our NATE-certified specialists.

Use our easy guide below to start troubleshooting your furnace. Most of these steps don’t require mechanical abilities.

Steps for Furnace Troubleshooting

Check the Thermostat

To begin, make sure your thermostat is instructing your furnace to turn on.

If you have a digital thermostat:

  • Swap out 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 showing the right 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 force the furnace to start if thermostat programming is causing a problem.
  • Increase the temperature setting to 5 degrees warmer than the room temperature.
Digital Thermostat

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 begin to run, your furnace may not have power.

If you have a smart thermostat—like one made by Nest, Ecobee, Lux, Honeywell or Bosch—troubleshooting is very model-specific. Take a look at the manufacturer’s website for help. If you still can’t get your Wi-Fi thermostat to work, contact us for assistance.

Lennox Smart Thermostat

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, look 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.
  • Look for 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,” don’t try to reset it and get in touch with a professional from Watts Electrical & Air Conditioning at 601-736-7362 right away.

Regardless of your furnace’s age or brand, it has at least one standard wall switch located on or close to 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 ignite. (If you don’t know where to find your furnace, look in your basement, garage or utility closet. It could also be in a crawl space or attic.)

Replace Your Furnace’s Air Filter

When it comes to furnace problems, a grungy, clogged air filter is frequently the top offender.

If your filter is too dirty:

  • Your furnace won’t be able to stay on, or it could overheat from reduced airflow.
  • Your energy bills could increase because your furnace is turning on more often.
  • Your furnace could fail too soon because a dirty filter causes it to work harder.
  • Your furnace can be cut off from power if an excessively dirty filter causes the breaker to trip.

Depending on what model 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.

Replacing a furnace filter

To replace your filter:

  • Turn off your furnace.
  • Take out the filter and tilt it toward the light. If you can’t see light through it, replace it.
  • Install the new filter with the arrow pointing toward the furnace to avoid damage.

Flat filters should be replaced every month, 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 sooner.

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

Examine the Condensate Pan

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

If water is seeping 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 full. If it needs to be drained, use a special pan-cleaning tablet you can get at home improvement or hardware stores.
  • If your pan contains a pump, inspect the float switch. If the switch is stuck “up” with liquid in the pan, contact Watts Electrical & Air Conditioning at 601-736-7362, because you will probably need a new pump.

Peek Inside Your Furnace

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

If you see anything except a steady, colored light or blinking green light, call Watts Electrical & Air Conditioning at 601-736-7362. Your furnace may be giving an error code that needs professional help.

Clean the Flame Sensor

If your furnace tries to start but switches off without distributing heat, a dirty flame sensor could be responsible. 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 HVAC professionals at Watts Electrical & Air Conditioning 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.
  • Remove the furnace’s front panel and follow the wire to the flame sensor.
  • Unscrew the rod and use your sandpaper, steel wool or emery cloth to lightly 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 go through a series of checks before continuing regular operation. If your furnace doesn’t start, the sensor may need to be replaced or something else might be wrong. If this happens, get in touch with Watts Electrical & Air Conditioning at 601-736-7362 for assistance.

Relight the Pilot Light

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

  • Look for 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.”
  • Press 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 Watts Electrical & Air Conditioning at 601-736-7362.

Check Your Fuel Source

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

Watts Electrical & Air Conditioning Can Help with Furnace Problems

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

Call us today at 601-736-7362 or use our online scheduler. We’ll come out and figure out the problem.

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