When your furnace won’t start, doing your own furnace repair in The Bay Area, California, 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 The Bay Area, Contra Costa Heating & AC 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 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
To begin, make sure your thermostat is instructing your furnace to turn on.
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” as opposed to “off” or “cool.”
Ensure the program is showing the right 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 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 started within a couple 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. Check the manufacturer’s website for help. If you still can’t get your Wi-Fi thermostat to work, call us at 510-343-9841 for heating and cooling service.
2. Examine Breakers and Switches
Next, you will need to check if your breaker and furnace switch are on.
Locate your house’s main electrical panel. If you aren’t sure 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.
Find 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 Contra Costa Heating & AC at 510-343-9841 right away.
No matter 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, anticipate your furnace could 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 problems, a filthy, clogged air filter is regularly the top offender.
If your filter is too dirty:
- Your furnace won’t stay on, or it could overheat from limited airflow.
- Your energy bills could be higher because your furnace is turning on too often.
- Your furnace could stop working prematurely because a dirty filter causes it to overwork.
- Your furnace can be cut off from power if an excessively dirty filter causes the breaker to trip.
Depending on what make 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:
- 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.
- Add the new filter with the arrow pointing toward the furnace to avoid damage.
Flat filters should be replaced once a month, while pleated filters should last about three months. You can also get 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
Also known as drain pans, condensate pans hold water your furnace pulls 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, take a look at the float switch. If the switch is stuck “up” with liquid in the pan, contact us at 510-343-9841, 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 verify 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 else besides a steady, colored light or blinking green light, call us at 510-343-9841 for HVAC service. Your furnace may be giving an error code that requires professional help.
6. Clean the Flame Sensor
If your furnace tries to start but turns off without blowing heat, a dirty flame sensor could be to blame. When this takes place, 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 by yourself. Or, one of our heating service specialists 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 trace 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 set of checks before resuming normal operation. If your furnace doesn’t ignite, the sensor may need to be replaced or something else could be wrong. If this happens, get in touch with us at 510-343-9841 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.
- 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 sparking 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, get in touch with us at 510-343-9841 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 510-343-9841 or contact us online. We’ll come out and figure out the problem.