DIYbanter - View Single Post - Furnace Problems - Blowing cold air

Tony Hwang

wrote:

Termostat fan was set to ON.
I set the termostat to HEAT and FAN option to: AUTO.

Now it's not doing anything. Pilot on our furnace is burning, but
burners are not ignited.
What could be the reason for burners not igniting?

Hi,
Can't you think logic? Thermostat sends heat command signal(24V AC on W
terminal) to furnace furnace gets the signal and actuate gas
valve valve opens gas flows pilot ignites the gas so on and
so on. Follow this logic flow and see where the trouble is. If it is
over your head, call the pro.