For homeowners with gas furnaces, it may be necessary to shut a furnace off and restart it to check the condition of the equipment and ensure that there is no gas leaking. For Goodman brand gas furnaces, you must follow the startup procedure exactly to ensure safety.
Before starting a furnace, homeowners should ensure that the furnace has adequate ventilation and there is nothing obstructing the vent pipe. Also, if a homeowner smells gas five minutes after shutting off the gas valve to the furnace and the electrical power to the furnace, he should contact his gas supplier for help and not use any appliances.
To start a Goodman furnace, switch the furnace's gas valve to the "On" position, close the burner compartment door, then open the external manual gas shut-off valve. Next, set the thermostat to a temperature that is above the current room temperature, wait until the burners light, and then adjust the thermostat to the temperature desired.
Homeowners should not try to light a Goodman gas furnace burner by hand. The furnace comes with an automatic ignition device that lights the burner.