When your furnace won’t start, doing your own furnace repair in Warrenton, Missouri, can feel pretty overwhelming.
Troubleshooting your furnace might feel like a complicated job when your heat won’t turn on. But it doesn’t have to be like that.
There are a few fast, inexpensive fixes you can do on your own 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 pro and live in Warrenton, Schraer Heating & Air Conditioning can assist 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 offer furnace installation.
While you’re chatting with us, think over a regular furnace maintenance plan that might help you avoid repairs in the future. We can tell you how often your furnace should be inspected by one of our Certified Pros.
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 signaling your furnace to ignite.
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 problems overriding the program, set the temperature by using the up/down arrows and press the “hold” button. This will force 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 started within several minutes, make sure it has power by toggling the fan switch from “auto” to “on.” If the fan doesn’t start, your furnace may not have power.
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 636-456-5041 for heating and cooling service.
2. Examine Breaks 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 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.
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,” don’t try to reset it and get in touch with a professional from Schraer Heating & Air Conditioning at 636-456-5041 right away.
Regardless of 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, 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 issues, a filthy, clogged air filter is regularly the top culprit.
If your filter is too dirty:
- Your furnace won’t keep heating your home, or it could overheat from reduced airflow.
- Your energy bills could be higher because your furnace is turning on more than it should.
- Your furnace could stop working prematurely because a dirty filter causes it to overwork.
- Your furnace can be cut off from power if an overly dirty filter causes the breaker to trip.
Depending on what make of furnace you have, your air filter is located 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.
- Take out the filter and tilt 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 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 often.
To make the process smoother in the future, use a permanent marker on your furnace housing or ductwork to indicate the airflow direction and filter size.
4. Inspect the Condensate Pan
Otherwise known as drain pans, condensate pans capture 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 full. If it needs to be drained, use a special pan-cleaning tablet you can buy at home improvement or hardware stores.
- If your pan uses a pump, take a look at the float switch. If the switch is stuck “up” with standing water in the pan, contact us at 636-456-5041, because you will possibly 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 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 636-456-5041 for HVAC service. Your furnace may be emitting an error code that is calling for professional help.
6. Clean the Flame Sensor
If your furnace tries to start but shuts off without blowing heat, a dirty flame sensor could be at fault. When this takes place, your furnace will make an attempt to turn onthree 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 experts 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
- 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 go through a set of checks before resuming regular operation. If your furnace doesn’t start, the sensor may need to be replaced or something else could be wrong. If this happens, contact us at 636-456-5041 for heating and cooling repair assistance.
7. Relight the Pilot Light
If you own 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.
- 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 sparking a fire.
- Turn the knob to “pilot.”
- Push 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 636-456-5041 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 636-456-5041 or contact us online. We’ll come out and figure out the problem.