Steps to Troubleshoot Your Furnace
First, check to make sure your thermostat is set to heat (This is especially important if your property uses a combination heating/cooling system)
Be sure the circuit breaker is on or that the fuse hasn’t blown. If you do notice a problem here, reset the circuit breaker or have the fuse replaced. If this happens again immediately, we recommend contacting a specialist as there is likely a shortage in the appliance or wiring in your home.
The motor may need to be reset because of an overload. Look for a reset button near the blower motor’s housing and press it. If the button is not readily available, check the manufacturer's guide for information on how to reset the motor.
Turn off the power to the furnace at the main electrical panel or subpanel. Look for a fuse in the power switch, and if it is blown, replace it.
With a gas furnace, the pilot light may have gone out or the gas valve may be shut off. Check the furnace’s ignition. For safety, if the pilot light has been extinguished for an unknown amount of time, be sure to shut off the valve completely and allow time for the gas to clear before attempting to relight the pilot.
If the furnace still doesn’t work, be sure the thermostat itself isn’t faulty. Repair or replace the unit as needed.
Additional information on preparing your home for winter can be found here: Winterizing Your Home