When your furnace won’t start, doing your own furnace repair in Phoenix, Arizona, can feel pretty overwhelming.
Figuring out a furnace-related problem might feel like an overwhelming task when your heat won’t work. But it doesn’t have to be like that.
There are several time-saving, reasonable fixes you can do by yourself to avoid 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 a heating and cooling professional and live in Phoenix, Integrity AC & Heating LLC can help you. We can repair most types of heating systems and also provide emergency furnace repair.
If you’re ready for a new heating system, we also do furnace installation.
While you’re talking with us, think over a regular furnace maintenance plan that might help you avoid breakdowns in the future. We can tell you how frequently your furnace should be checked by one of our NATE-certified professionals.
Use our easy guide below to get started on troubleshooting your furnace. Most of these steps don’t require mechanical abilities.
Furnace Repair Checklist
1. Check the Thermostat
To start, make sure your thermostat is instructing your furnace to start.
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 displaying the appropriate day and time and is set to “run.” If you’re having a hard time overriding the program, set the temperature by using the up/down arrows and press the “hold” button. This will cause the furnace to turn on 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 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. Check the manufacturer’s website for help. If you still can’t get your Wi-Fi thermostat to work, call us at 602-971-0567 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 have no idea 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.
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 get in touch with a professional from Integrity AC & Heating LLC at 602-971-0567 right away.
No matter your furnace’s age or brand, it has at least one standard wall switch located on or near 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, 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 breakdown, a grungy, clogged air filter is often the top culprit.
If your filter is too dirty:
- Your furnace won’t stay on, or it could overheat from reduced airflow.
- Your energy bills could go up because your furnace is turning on too often.
- Your furnace could break down too soon 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 can be found inside the blower compartment of your furnace, an attached filter case or wall-mounted return air grille.
To replace your filter:
- Turn off your furnace.
- Pull out the filter and angle it toward the light. If you can’t see light through it, use a new one.
- Put in 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 use a washable filter that will last about 10 years. If you have children or pets, you may have to change 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 list the airflow direction and filter size.
4. Inspect the Condensate Pan
Also known as drain pans, condensate pans hold water your furnace draws 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 purchase at home improvement or hardware stores.
- If your pan contains a pump, take a look at the float switch. If the switch is stuck “up” with liquid in the pan, contact us at 602-971-0567, because you will likely need a new pump.
5. Check for Furnace Error Codes
If malfunctions keep on happening, peek 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 other than a steady, colored light or blinking green light, call us at 602-971-0567 for HVAC service. Your furnace may be emitting an error code that is calling for professional assistance.
6. Clean the Flame Sensor
If your furnace tries to start but shuts off without putting out heat, a dirty flame sensor could be to blame. When this occurs, your furnace will attempt to turn on 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 on your own. 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:
- Disable 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 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 might run through a sequence of checks before continuing normal operation. If your furnace doesn’t ignite, the sensor may need to be replaced or something else may be wrong. If this happens, contact us at 602-971-0567 for heating and cooling repair assistance.
7. Relight the Pilot Light
If you have 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 starting 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 602-971-0567 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 602-971-0567 or contact us online. We’ll come out and figure out the problem.