When your furnace won’t start, doing your own furnace repair in Dundas and Northfield, Minnesota, 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 Dundas and Northfield, Better Air 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

To start, make sure your thermostat is telling your furnace to start.

Digital Thermostat

Replace 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 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 cause the furnace to start if thermostat programming is causing a problem.

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

If your furnace hasn’t kicked on within a couple minutes, make sure it has power by toggling the fan switch from “auto” to “on.” If the fan doesn’t start, 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 507-663-1208 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.

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,” don’t touch it and call a professional from Better Air at 507-663-1208 right away.

Regardless of 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, anticipate your furnace could take up to five minutes to ignite. (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 breakdown, a filthy, clogged air filter is frequently to blame.

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 fail sooner than it should because a dirty filter causes it to overwork.
  • Your furnace can be cut off from power if an extremely dirty filter causes the breaker to trip.

Depending on what type 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. Remove the filter and hold it up to the light. If you can’t see light through it, use a new one.
  3. Install 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 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

Otherwise known as drain pans, condensate pans capture 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’s clear. If it needs to be drained, use a special pan-cleaning tablet you can buy at home improvement or hardware stores.
  • If your pan has a pump, take a look at the float switch. If the switch is stuck “up” with water in the pan, contact us at 507-663-1208, because you will probably need a new pump.

5. Check for Furnace Error Codes

If malfunctions keep on happening, 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 else besides a steady, colored light or blinking green light, call us at 507-663-1208 for HVAC service. Your furnace may be communicating an error code that is calling for professional help.