Read These Furnace Repair Suggestions Before Calling a Pro in Allen, TX

It can feel anxiety-inducing when you have a chilly home in Allen because your furnace won’t kick on.

Here’s the good news—you might be able to avoid a furnace repair call with our troubleshooting information. You don’t need any special skills. Plus, many of these solutions are affordable (or even no cost).

This guide might help you mend your furnace when it:

  • Won’t switch on
  • Won’t light
  • Won’t stay on

What to Do When You Need Furnace Repair

Tri County Air Care LLC can help when you need a technician in Allen.

Our furnace repair services include all makes and models. If you need a new HVAC system, we also offer furnace replacement and furnace installation.

If your heat has ceased working, it might be due to skipping regular furnace maintenance. Normal service often helps us spot costly problems before they start, and could help your furnace run more efficiently.

During regular service, our certified pros will:

  • Observe your furnace
  • Make sure it’s running correctly
  • Lubricate moving parts

A furnace that’s regularly serviced often lasts longer and operates more efficiently. That could help you save more on your monthly bill.

How to Troubleshoot Your Furnace

Ready to try repairing your furnace alone? Use our step-by-step instructions below.

Steps for Furnace Troubleshooting

Make Sure Your Thermostat is Working

The first step is to check your thermostat, because it may not be asking for heat.

Digital Thermostat

  • Empty screen? Trade out the batteries. If the display is scrambled, you may need to shop for a new thermostat.
  • Check to see if the switch is set to “heat,” not “off” or “cool.”
  • Is the program on the correct day and set to “run”? You can also override it by using the up/down arrows and pressing the “hold” button. This will start the thermostat if your programming is questionable.
  • Set the wanted temp 5 degrees warmer than the current temperature.
Digital Thermostat

Your furnace should kick on within just a few minutes. If it stays off, look at its power supply by sliding the fan switch from “auto” to “on.” If the fan doesn’t work, your furnace may not have power.

Smart Thermostat

Do you have one of these popular Wi-Fi thermostats? Find manufacturer-specific support and troubleshooting tips below.

Lennox Smart Thermostat

Reach out to us at 469-213-8367 if you still can’t get your smart thermostat to run.

Inspect Breakers and Switches

After troubleshooting your thermostat, you will want to check your breaker box and furnace switch.


  • Find your home’s electrical panel, a gray metal box on the wall in your garage, basement or closet.
  • Be sure your hands and feet are dry.
  • Find the “furnace” or “heat” breaker and make sure it’s in the “on” position. It may be in the middle or “off” position if it’s tripped.
  • If the breaker has tripped, use one hand to slide it to the “on” spot. If the breaker instantly trips again, don’t touch it. Call us at 469-213-8367 as soon as possible.

Furnace Switch

Regardless of age or manufacturer, your heater will have a regular light switch on or near it.

Not sure where to spot your furnace? Check your:

  • Basement
  • Garage
  • Utility closet
  • Crawl space
  • Attic

Once you’ve discovered your furnace, examine the switch. It should be in the “on” position, with the switch flipped up. Your furnace could take up to five minutes to start if the switch was unintentionally turned off.

Get a New Air Filter

When your furnace won’t operate correctly, an excessively dirty or dusty air filter is often the culprit.

Here’s what can happen when you’re late for a filter replacement:

  • A dirty filter can trip your furnace’s breaker, cutting off power.
  • Restricted airflow can cause your furnace to overheat and shut down too quickly.
  • Your furnace could run more frequently (short cycling) and negatively impact your energy bills.
  • You may need to replace your furnace sooner because it is running more often.

How to Exchange Your Furnace Filter

Your furnace’s air filter may be located in the blower compartment, attached filter case or wall-mounted return air grille.

Replacing a furnace filter

When putting in a new filter:

  1. Switch off your furnace.
  2. Take out the filter. Angle it toward the light. Can you see through it? If not, it’s time to replace it.
  3. Put in the new filter with the arrow pointing toward your furnace. Use a permanent marker on your furnace to list the airflow direction and filter size for next time.

Here’s how long filters often last:

  • Flat filters—one month
  • Pleated filters—three months
  • Washable filters—10 years

You should replace your filter more often if you have children, pets or allergies.

Investigate the Condensate Pan

Condensate pans, or drain pains, hold the water your furnace takes from the air.

Is your furnace leaking water? Or maybe there’s still water in the pan? Follow these steps.

Pan with PVC Pipe/Drain

Use a pan-cleaning tablet from a home improvement or hardware store. This will free up the pipe or drain.

Pan with Pump

Contact us at 469-213-8367 if your float switch is “up” and there’s water in the pan. You will probably need to have your pump replaced.

Examine Inside Your HVAC System

Your furnace might be showing you an error code. Check inside the plastic window on the front or side of your furnace.

When your furnace is working right, the light should be a stable, colored light or blinking green light. It uses a flashing red light to communicate a fault code when something’s not right.

Call us at 469-213-8367 if you’re getting an error code and we’ll fix the problem as soon as we can.

Get Rid of Gunk from Your Flame Sensor

Your flame sensor could be causing issues if your furnace tries to turn on but shuts off without pushing out heat.

A telltale sign is your furnace trying to start three times before a safety feature turns it off for about an hour.

You can clean this part yourself if you feel comfortable opening your furnace. Or we can help—just call 469-213-8367 for help.

Cleaning Your Flame Sensor

You’ll need:

  1. ¼” hex screwdriver or wrench
  2. Light-grit sandpaper, steel wool or emery cloth
  3. Paper towel

Before you start, stop power to your furnace by way of its breaker switch. Turn off the gas as well if the gas valve isn’t electric.

  • Remove your furnace’s front panel and trace the wire to the flame sensor. It looks like a thin, bent rod.
  • Carefully unscrew the rod and delicately clean it using sandpaper, steel wool or emery cloth.
  • Wipe off the rod with a paper towel.
  • Replace the sensor and put your furnace door back on.
  • Restore power to your equipment, which may go through a series of tests before turning on. If it doesn’t start, you may need a new sensor or something else might be wrong. Call us at 469-213-8367 if this happens.

Reignite the Pilot Light

If you have an older furnace, its pilot light might be out. Look for information on the label on your furnace’s doors.

You can also take these steps:

  • Locate the switch on the bottom of your furnace labeled “pilot.”
  • Change the switch to the “off” position.
  • Pause for at least five minutes to avoid starting a fire.
  • Return the switch to “pilot.”
  • Hold down the “reset” button as you bring a lit long lighter to the pilot light opening.
  • Release the “reset” button once you light your furnace.

Tried these steps twice but your pilot light won’t light or stay lit? Give us a call at 469-213-8367.

Check Other Gas Appliances

Do your other natural gas appliances work? If not, there may be a problem with your gas service. Or you may have run out of propane.

We Can Fix Furnace Complications

Tried our troubleshooting guide but your furnace still won’t turn on?

Call us at 469-213-8367 or use our form to request an appointment today. We’ll visit your home and quickly fix the problem.