Use this troubleshooting checklist if your furnace won't start
October 14, 2015

No one should go without heat in Lawton, OK. So if your furnace won’t start, try this troubleshooting checklist before calling your local technician for help.

1) Make sure the thermostat is set to “Heat”

And while you’re at it, ensure the temperature is set 5 degrees above the room temperature.

2) Ensure the furnace power switch is set to “On”

You furnace has a power switch next to it. Someone may have switched it to “off” by accident because they thought it was an attic or basement light switch.

Just so you know what the switch looks like, refer to this diagram:


3) Check the air filter

The filter may be dirty and is causing the furnace to overheat. Change the filter as needed. You may find the filter at a return register or near the furnace itself, as pictured here:



4) Open and unblock all your supply registers

Closing off more than 20 percent of the registers in your house can cause high resistance and unnecessary heat build-up in the furnace, according to AHRI. Too much heat can cause the furnace to overheat and shut down. So keep those vents open.

Also, make sure you don’t have any curtains, drapes or furniture blocking any of the supply vents.

5) Check the pilot light

Do you have an old furnace with a standing pilot light? Open the furnace door to see if it’s lit. If not, you found your problem.

Try to relight the pilot light with these step-by-step instructions.

6) Check the circuit breaker

A power surge may have shut off your furnace.

To fix this:

  1. Turn off your furnace at the power switch.
  2. Check your circuit breaker panel and look for a tripped breaker.
  3. If tripped, flip the switch to the “off” position, then back to “on.”
  4. Turn the furnace back on.

For everything else, there’s a furnace technician

If your furnace does not work after trying these solutions, you’ll need a tech’s help.

If you live in the Lawton, OK area. Pippin Brothers is just around the corner. Contact us online for help.

Pippin Brothers is the Lawton-area’s most trusted heating, air conditioning and plumbing company. We’ve been serving Oklahoma since 1978. Contact us for more information.