Furnace Won’t Turn On? Here’s What to Check

It’s the first freezing cold night of the year in Chicagoland and you go to switch on the furnace… and nothing happens. What should you do? It could be an simple fix, so here’s what to check:

1. Check That the Power Is On – Even though it’s gas powered, a furnace requires electricity to run, so check the power to the unit at the circuit breaker panel. If a circuit is tripped, switch it back to the ON position. Note, if the circuit trips again, DO NOT RESET IT MORE THAN ONCE, this is a safety measure to prevent an electrical fire in the event of a malfunction. Have an electrician inspect the system.
2. Check the Thermostat Is Turned To the HEAT Position, then try turning the temperature up a couple degrees for testing purposes.
3. Check the Furnace Condensate Pan (Drain Pan)- During normal operation water will drain from the air conditioner or furnace into a pan. If the drain for the pan is clogged the pan will fill up and trigger a float switch, preventing the operation of the furnace. If the float switch is up (activated), you will need to clear the obstruction to allow water to empty and then reset the switch.
4. Check the Furnace Filter. An extremely dirty and clogged filter will make the furnace overheat, which will cause it to shut down as a safety precaution. Install a new filter to allow it to breathe easier.
5. Check the Pilot Light. This only applies to older gas furnaces. Most newer units have electric ignition. If your pilot light is out consult your owner’s manual for the correct way to light the pilot.
6. Check the Fuel Supply. If there are other gas appliances in the home, such a gas range or fireplace, check that they are functioning.

If none of the above steps works and the furnace still won’t turn on, call ABC Plumbing, Sewer, Heating, Cooling and Electric. We’ll get the heat back on in no time.