Furnace Repair in Florissant, MO: How to Repair 9 Regular Issues

HVAC man working on a furnace

When your HVAC system won’t kick on, doing your own furnace repair in Florissant, MO, can seem daunting.

There are several time-saving, low-cost fixes you can take on on your own to avoid a heating repair call.

If your heating system doesn’t start, won’t stay on or won’t fire, try the troubleshooting list below in advance of contacting an HVAC pro.

If you come to the realization you need help from a heating and cooling pro and live in Florissant, B & B Heating & Cooling can assist you. We are able to repair most brands of furnaces.

CALL NOW 314-325-7552



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

While you’re chatting with us, think over an annual furnace maintenance plan from B & B Heating & Cooling that may help you avoid breakdowns in the future. We can inform you about how regularly your heater ought to be checked by one of our NATE-Certified professionals.

Follow our straightforward guide as shown to get started on troubleshooting your heating system. Most of these procedures don’t require mechanical abilities to complete your furnace repair.

Furnace Repair Checklist

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1. Examine the Thermostat

To begin, make sure your thermostat is instructing your heat to start.

Digital Thermostat

  • Swap out the batteries if the monitor is blank. If the digital screen is jumbled, the thermostat could need to be swapped out.
  • Ensure the switch is set to “heat” instead of “off” or “cool.”
  • Ensure the program is showing the appropriate day and time and is programmed to “run.” If you’re having problems turning off the schedule, regulate the temperature by using the up/down arrows and holding the “hold” button. This will force the heating to start if thermostat settings are a problem.
  • Turn the temperature setting to 5 degrees above what the room temperature currently is.

If your furnace hasn’t started within several minutes, make certain that it has juice by changing the fan switch from “auto” to “on.” If the fan doesn’t start, your heating system could be without power.

Smart Thermostat

If you have a smart thermostat—like one designed by Nest, Ecobee, Lux, Honeywell or Bosch—troubleshooting is very model-specific. Check the manufacturer’s website for support. If you aren’t able to get your Wi-Fi thermostat to function, calll us at 314-325-7552 for heating and cooling service.

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2. Check Breakers and Switches

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

  • Locate your residence’s main electrical panel. If you don’t know where it is, keep an eye out for a silver metal box in your basement, garage or closet.
  • Make certain that your hands and feet are dry in advance of using the panel or breakers.
  • Find the breaker titled “furnace” or “heat,” and ensure it’s switched “on.” If the breaker has tripped, it will be in the middle or “off” position.
  • With one hand, firmly flip the breaker to the “on” location. If the breaker immediately trips and pops back to “off,” don’t try to reset it and call an expert from B & B Heating & Cooling at 314-325-7552 right away.

Regardless of your furnace’s age or brand, it has at least one ordinary wall switch placed on or close to it.

  • Make sure the control is facing up in the “on” spot. If it was shut off, expect your furnace to take up to five minutes to ignite. (If you don’t know where to locate your furnace, look in your basement, garage or utility closet. It may also be in a crawl space or attic.)
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3. Buy a New Air Filter

When it comes to furnace breakdowns, a filthy, blocked air filter is often to blame.

If your filter is too grungy:

  • Your furnace won’t keep heating your home, or it could get too warm from reduced airflow.
  • Your energy costs might be higher because your heating system is running too often.
  • Your furnace could fail too soon since a dusty filter causes it to work harder.
  • Your heating may be cut off from power if an extremely dirty filter is the cause of a tripped breaker.

While it depends on what make of heating system you use, your air filter can be found in the interior of the blower compartment of your heater, an attached filter case or wall-mounted return air grille.

To put in a new filter:

  • Cut the power to your heater.
  • Remove the filter and hold it up to the light. If you can’t view light through it, use a new one.
  • Put in the new filter with the arrow pointing toward the heating system to avoid damage.

Flat filters should be replaced monthly, while pleated filters should work about three months. You may also use a washable filter that you can use for about 10 years. If you have children or pets, you might have to change your filter more frequently.

To make the process easier down the line, draw with a permanent pen on your heater housing or ductwork to list the airflow direction and filter size.

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4. Inspect the Condensate Pan

Also known as drain pans, condensate pans catch water your furnace draws from the air.

If water is seeping out of your heating system or its pan is overflowing, follow these steps.

  • If your pan includes a drain (look for a PVC pipe), double-check that it isn’t full. If it requires draining, 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 lever is jammed “up” with liquid in the pan, contact us at 314-325-7552, because you will possibly have to buy a new pump.
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5. Watch for Furnace Error Codes

If malfunctions keep on happening, look within your furnace’s plastic window to check the blower motor’s status. Subject to the type, the light could also be attached on the surface of your heating system.

If you note anything except an uninterrupted, colored light or twinkling green light, contact us at 314-325-7552 for HVAC service. Your heater might be communicating an error code that requires specialized help.

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6. Brush off the Flame Sensor

If your furnace attempts to run but turns off without blowing heat, a filthy flame sensor can be to blame. When this happens, your furnace will make an attempt to turn on three times before a safety feature turns it off for approximately an hour.

If you feel confident with opening up your heating system, cleaning your flame sensor is a task you have the ability to do on your own. Or, one of our heating service specialists has the ability to complete it for you.

If you are fine with cleaning the sensor yourself, you require:

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

As the next step:

  • Disable the furnace’s power with its wall switch or breaker. If you don’t have an electric gas valve, you have to shut off the gas as well.
  • Lift off the furnace’s front panel and trace the wire to the flame sensor.
  • Remove the rod and use your sandpaper, steel wool or emery cloth to gently rub the metal rod.
  • Wipe off the rod with a paper towel.
  • Put the sensor back in.
  • Secure the furnace doors.
  • Turn the furnace’s power back on. It may proceed through a set of checks before proceeding with regular heating. If your heating system doesn’t ignite, the sensor might need to be replaced or something else could be causing a problem. If this happens, get in touch with us at 314-325-7552 for heating and cooling repair help.
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7. Relight the Pilot Light

If you own an outdated furnace, the pilot light could be out. To reignite it, locate the guide on a sticker on your heating system, or use these guidelines.

  • Find the toggle beneath your heater marked “pilot,” “on” and “off.”
  • Move the switch to the “off” position.
  • Take a break for at least five minutes to avoid starting a fire.
  • Move the dial to “pilot.”
  • Push the “reset” lever as you push the flame of a long lighter to the pilot light opening.
  • Depress the “reset” button once the pilot light is ignited.
  • If you have used the guide twice and the pilot light still won’t burn or stay lit, get in touch with us at 314-325-7552 for furnace service.

condensate pan icon

Examine Your Energy Delivery System

Try switching on an additional gas appliance. If it doesn’t operate, your natural gas source may be shut off, or you may have run out of propane.

We Can Help with HVAC Repair

Gone through our troubleshooting guide but your heating system still won’t run?

Call us right away at 314-325-7552 or contact us online. We’ll come to your house and figure out the trouble.

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