When your furnace won’t start, doing your own furnace repair in Marshfield, Wisconsin, can feel pretty overwhelming.
Troubleshooting your furnace might feel like an overwhelming process when your heat won’t power on. But it doesn’t have to be like that.
There are a few speedy, low-cost 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 calling an HVAC professional.
If you find you need help from a heating and cooling pro and live in Marshfield, House of Heating Incorporated can help you. We can repair most types of heating systems and also provide emergency furnace repair.
If you need a new heating system, we also do furnace installation.
While you’re talking with us, think over a routine furnace maintenance plan that may help you avoid problems in the future. We can tell you how frequently your furnace should be checked by one of our certified professionals.
Use our easy guide below to start troubleshooting your furnace. Most of these steps don’t require mechanical know-how.
Furnace Repair Checklist
1. Check the Thermostat
To start, make sure your thermostat is telling your furnace to ignite.
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” rather than “off” or “cool.”
Ensure the program is set to the correct 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 make the furnace to start 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 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 715-384-3163 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 don’t know 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 touch it and call a professional from House of Heating Incorporated at 715-384-3163 right away.
No matter your furnace’s age or brand, 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, look in 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 dirty, clogged air filter is frequently the top offender.
If your filter is too dirty:
- Your furnace won’t stay on, or it could overheat from restricted airflow.
- Your energy bills could increase because your furnace is turning on more than it should.
- Your furnace could stop working too soon because a dirty filter causes it to overwork.
- Your furnace can be disconnected from power if an extremely dirty filter causes the breaker to trip.
Depending on what model of furnace you have, 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 tilt it toward the light. If you can’t see light through it, use a new one.
- 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 smoother 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
Commonly known as drain pans, condensate pans capture water your furnace removes 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 contains a pump, inspect the float switch. If the switch is stuck “up” with liquid in the pan, contact us at 715-384-3163, because you will probably need a new pump.
5. Check for Furnace Error Codes
If malfunctions keep on happening, take a look 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 715-384-3163 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 blowing heat, a dirty flame sensor could be responsible. When this happens, 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.
- 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 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 could proceed through a set of checks before proceeding with usual operation. If your furnace doesn’t ignite, the sensor may need to be replaced or something else may be wrong. If this happens, call us at 715-384-3163 for heating and cooling repair assistance.
7. Relight the Pilot Light
If you are using an older furnace, the pilot light could be extinguished. To relight it, find the instructions on a label on your furnace, or follow these steps.
- Find 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 creating 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, contact us at 715-384-3163 for furnace service.
Check Your Fuel Source
Try using another gas appliance. If it doesn’t work, your natural gas service could be turned off, or you could be out of propane.