How to Troubleshoot a Down Draft Furnace

Ensure the downdraft furnace power switch is turned to “On” if the furnace is not working or heating as expected. If the furnace is turned on but is not heating, reset or replace the fuse or circuit breaker. If the electrical outlet is working and the furnace is on, set the thermostat to “Warm” and turn the thermostat temperature to a warmer setting.

Check all vents and registers if the furnace is running constantly or the heat level is not accurate based on the thermostat setting. Open all registers and remove any items that might be blocking air flow.

Look at the condensate drain system if there is leaking around the drain. Check for debris and clean it away to make sure the drain valve can operate correctly.

Restart the downdraft furnace if power is lost or the pilot light goes out. Shut off all power to the furnace, lower the furnace thermostat setting and then open the access panel. Rotate the gas valve to “Off” and then step away for five minutes to let gas clear away from the lines. Smell carefully for gas after five minutes and leave the home if you detect gas. Call your gas company or emergency services if you suspect a gas leak. If not, continue and turn the knob to “On” and shut the access panel. Turn on the furnace power and increase the thermostat temperature.

Remove the filter, which is located in the upper portion of the furnace through the access door, if the furnace is running loudly or is not heating well. Clean the filter with soapy water and rinse it well. Let the filter dry well and then put the filter back in the furnace and close the access door.