Furnace Repair in Jefferson City, MO

HVAC man working on a furnace

When your heater won’t start, doing your own furnace repair in Jefferson City, MO, can feel daunting.

There are a few quick, low-cost fixes you can take care of yourself to skip a HVAC repair bill.

If your heater won’t start, won’t run consistently or won’t ignite, try the troubleshooting checklist below prior to contacting an HVAC expert.

If you find you need support from a heating and cooling professional and live in Jefferson City, Stieferman Heating Company Inc can assist you. We are able to repair most brands of furnaces.

CALL NOW 573-635-3547

If it’s time for a new furnace, we also offer furnace installation.

While you’re chatting with our team, consider a routine furnace maintenance plan from Stieferman Heating Company Inc that could help you avoid repairs down the road. A team member can let you know how frequently your heater needs to be examined by one of our NATE-certified professionals.

Go through our straightforward guide as shown to start troubleshooting your heater. A great deal of these procedures don’t have a need for mechanical abilities to complete your furnace repair.

Furnace Repair Checklist

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1. Inspect the Thermostat

First, ensure your thermostat is signaling your heater to ignite.

Digital Thermostat

  • Change the batteries if the display is not displaying anything. If the digital monitor is mixed up, the thermostat may need to be changed.
  • Ensure the switch is switched to “heat” instead of “off” or “cool.”
  • Ensure the program is set to the correct day and time and is scheduled to “run.” If you’re having problems getting out of the setting, set the temperature with the up/down arrows and pressing the “hold” button. This will cause the furnace to ignite if thermostat is causing a problem.
  • Turn the temperature setting to 5 degrees hotter than what the room temperature currently is.

If your furnace hasn’t kicked on within a few minutes, make certain that it has electricity by toggling the fan switch from “auto” to “on.” If the fan doesn’t operate, your furnace might not have power.

Smart Thermostat

If you utilize a smart thermostat—such as one made by Nest, Ecobee, Lux, Honeywell or Bosch—troubleshooting will be determined by the model you have. Refer to the manufacturer’s website for support. If you aren’t able to get your Wi-Fi thermostat to operate, reach us at 573-635-3547 for heating and cooling service.

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2. Check Breakers and Switches

Next, confirm your breaker and furnace switch are on.

  • Find your main electrical panel. If you don’t know where it is, look for a gray metal box in your basement, garage or closet.
  • Ensure your hands and feet are dry prior to opening the panel or breakers.
  • Find the breaker labeled “furnace” or “heat,” and ensure it’s switched “on.” If you find that the breaker tripped, it will be in the middle or “off” position.
  • Moving one hand, steadily switch the breaker to the “on” position. If the breaker instantly trips and pops back to “off,” don't try to reset it and contact an expert from Stieferman Heating Company Inc at 573-635-3547 immediately.

It doesn’t matter how old your furnace is or what brand it is, it has at least one standard wall switch installed on or close to it.

  • Make certain the switch is facing up in the “on” position. If it was turned off, expect your furnace to take up to five minutes to ignite. (If you don’t know where to locate your furnace, check your basement, garage or utility closet. It can also be in a crawl space or attic.)
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3. Get a New Air Filter

When it comes to heating problems, a dirty, clogged air filter is regularly the top culprit.

If your filter is too dirty:

  • Your heating system won’t be able to stay on, or it may get too hot from restricted airflow.
  • Your energy expenses may increase because your heat is working more often.
  • Your heater could fail prematurely since a dirty filter forces it to work harder.
  • Your heating system can lose power if an overly dirty filter results in a tripped breaker.

While it depends on what model 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 put in a new filter:

  • Turn off your heating system.
  • Remove the filter and angle it toward the light. If you can’t see light through it, get a new one.
  • Insert the new filter with the arrow pointing toward the heater to keep damage from happening.

Flat filters ought to be replaced once a month, while pleated filters should last about three months. If you have children or pets, you could have to change your filter more frequently.

To make changing your filter easier in the future, use a permanent marker on your heating system outside or ductwork to list the airflow direction and filter size.

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4. Examine the Condensate Pan

Commonly known as drain pans, condensate pans catch moisture your heater removes from the air.

If moisture is leaking from within your heater or its pan has too much water in it, try these recommendations.

  • If your pan has a drain (look for a PVC pipe), check that it’s clear. If it should be drained, drop in a special pan-cleaning tablet you can purchase at home improvement or hardware stores.
  • If your pan uses a pump, check the float switch. If the switch is jammed “up” with standing water in the pan, reach us at 573-635-3547, because you will probably have to get a new pump.
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5. Look for Heater Error Codes

If faults persist, look at your heater’s plastic window to verify the blower motor’s status. Subject to the model, the light might also be fixed on the outside of your heater.

If you see anything other than an uninterrupted, colored light or blinking green light, contact us at 573-635-3547 for HVAC service. Your furnace could be communicating an error code that is calling for specialized help.

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6. Scrub the Flame Sensor

If your heating system tries to operate but shuts off without blowing warmth, a grimy flame sensor could be to blame. When this occurs, your heater will attempt to ignite three times before a safety device turns it off for approximately an hour.

If you feel okay with taking the panels off your heater, gently scrubbing your flame sensor is something you are able to do yourself. Or, one of our heating service experts can complete it for you.

If you are fine with cleaning the sensor on your own, you should have:

  • A 1/4” hex screwdriver or wrench
  • Portion of light grit sandpaper, steel wool or emery cloth
  • A dry, clean paper towel


  • Turn off the heater’s power by using its wall switch or breaker. If your furnace’s gas valve isn’t electric, you have to switch off the gas along with it.
  • Remove the heating system’s front panel and trace the wire to the flame sensor.
  • Take off the rod and use your sandpaper, steel wool or emery cloth to lightly clean the metal rod.
  • Clear the rod with a paper towel.
  • Put the sensor back in.
  • Put the furnace doors back on.
  • Switch the furnace’s power back on. It may go through a set of inspections before resuming usual operation. If your heating system doesn’t start, the sensor might have to be replaced or something else could be wrong. If this occurs, get in touch with us at 573-635-3547 for heating and cooling repair assistance.
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7. Reignite the Pilot Light

If you own an aging furnace, the pilot light could be turned off. To reignite it, find the directions on a sheet on your heater, or try these steps.

  • Find the switch beneath your heater labeled “pilot,” “on” and “off.”
  • Move the switch to the “off” position.
  • Wait at least five minutes to prevent starting a fire.
  • Turn the switch to “pilot.”
  • Hold down the “reset” switch as you bring the flame of a long lighter to the pilot light opening.
  • Let go of the “reset” button once the pilot light is burning.
  • If you have gone through the list twice and the pilot light still won’t ignite or stay ignited, contact us at 573-635-3547 for furnace service.

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Examine Your Energy Source

Try using another gas appliance. If it doesn’t work, your natural gas source could be shut off, or you could be out of propane.

We Can Assist With Furnace Servicing

Gone through our troubleshooting sheet but your heating system still won’t heat?

Reach us today at 573-635-3547 or contact us online. We’ll come out and figure out the problem.


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