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

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

There are a few speedy, inexpensive fixes you can do on your own to prevent 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 pro and live in Sacramento, Bishop’s HVAC can assist you. We can repair most makes of heating systems and also provide emergency furnace repair.

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

While you’re talking with us, consider an annual furnace maintenance plan that could help you avoid problems in the future. We can tell you how frequently your furnace should be inspected by one of our Certified Pros.

Follow our easy guide below to get to work on troubleshooting your furnace. Most of these steps don’t require mechanical skills.

Furnace Repair Checklist

1. Check the Thermostat

First, make sure your thermostat is instructing your furnace to start.

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” rather than “off” or “cool.”

Ensure the program is displaying the appropriate day and time and is set to “run.” If you’re having trouble 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 an issue.

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

If your furnace hasn’t turned on within few minutes, make sure it has power by toggling the fan switch from “auto” to “on.” If the fan doesn’t start, your furnace could be without 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 916-591-6889 for heating and cooling service.

2. Examine Breakers and Switches

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

Find your house’s main electrical panel. If you have no idea 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.

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 Bishop’s HVAC at 916-591-6889 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 issues, a filthy, clogged air filter is frequently to blame.

If your filter is too dirty:

  • Your furnace won’t be able to stay on, or it could overheat from restricted airflow.
  • Your energy bills could increase because your furnace is turning on too often.
  • Your furnace could fail too soon because a dirty filter causes it to work overtime.
  • 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 have, 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 hold it up to the light. If you can’t see light through it, get a new one.
  3. Add 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 use 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 frequently.

To make the process easier 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 catch water your furnace pulls from the air.

If water is leaking 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 purchase at home improvement or hardware stores.
  • If your pan has a pump, inspect the float switch. If the switch is stuck “up” with liquid in the pan, contact us at 916-591-6889, because you will possibly need a new pump.

5. Check for Furnace Error Codes

If malfunctions persist, 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 else besides a steady, colored light or blinking green light, call us at 916-591-6889 for HVAC service. Your furnace may be giving an error code that requires professional help.

6. Clean the Flame Sensor