When your furnace won’t start, doing your own furnace repair in Cottonwood & Prescott, Arizona, can feel overwhelming.

Figuring out a furnace-related problem might feel like a challenging task when your heat won’t turn on. But it doesn’t have to be like that.

There are a couple of fast, reasonable fixes you can do by 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 getting in touch with an HVAC professional.

If you find you need help from a heating and cooling expert and live in Cottonwood & Prescott, Connolly Electric & Mechanical can provide assistance to you. We can repair most types of heating systems and also provide emergency furnace repair.

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

While you’re chatting with us, think over a routine 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 NATE-Certified Professionals.

Use our easy guide below to get to work on troubleshooting your furnace. Most of these steps don’t require mechanical know-how.

Furnace Repair Checklist

1. Check the Thermostat

First, make sure your thermostat is signaling your furnace to ignite.

Digital Thermostat

Change 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 appropriate 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 turn on if thermostat programming is causing an issue.

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 may 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 928-251-4327 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 don’t know where it is, keep an eye out 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,” leave it alone and get in touch with a professional from Connolly Electric & Mechanical at 928-251-4327 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, it could take your furnace up to five minutes to turn on. (If you don’t know where to find your furnace, take a look at 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 issues, a filthy, clogged air filter is regularly to blame.

If your filter is too dirty:

  • Your furnace won’t keep heating your home, or it could overheat from limited airflow.
  • Your energy bills could increase because your furnace is turning on more often.
  • Your furnace could stop working too soon because a dirty filter causes it to overwork.
  • Your furnace can be cut off from power if an overly dirty filter causes the breaker to trip.

Depending on what model of furnace you own, your air filter can be found 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. Take out the filter and tilt it toward the light. If you can’t see light through it, replace it.
  3. 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 replace your 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

Otherwise 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 get at home improvement or hardware stores.
  • If your pan contains a pump, inspect the float switch. If the switch is stuck “up” with water in the pan, contact us at 928-251-4327, because you will possibly need a new pump.

5. Check for Furnace Error Codes

If malfunctions keep on happening, look inside your furnace’s plastic window to confirm the status of the blower motor. Depending on the model, the light could also be mounted on the outside of your furnace.

If you see anything except a steady, colored light or blinking green light, call us at 928-251-4327 for HVAC service. Your furnace may be communicating an error code that needs professional help.

6. Clean the Flame Sensor

If your furnace tries to start but turns off without distributing heat, a dirty flame sensor could be to blame. When this takes place, your furnace will try to start three times before a safety feature shuts it down for about an hour.

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

  • Shut 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.
  • Take off 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 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 proceed through a series of checks before proceeding with regular operation. If your furnace doesn’t ignite, the sensor may need to be replaced or something else could be wrong. If this happens, contact us at 928-251-4327 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 sparking a fire.
  • Turn the knob to “pilot.”
  • Push 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, get in touch with us at 928-251-4327 for furnace service.

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.

We Can Help with HVAC Repair

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

Call us today at 928-251-4327 or contact us online. We’ll come out and figure out the problem.

Request Service