View Full Version : Furnace will not ignite in Auto mode.

Dec 17, 2006, 10:31 AM
I have an Armstrong-Air Gas-Fired furnace G1D91AU and a programmable thermostat which when I set to heat and says system on but the furnace is not turning on. If I set the thermostat to ON the furnace runs but is blowing cold air. It this a problem with my thremostat or my furnace itself?

I would appreciate if you can give me an idea where the problem is.


Dec 17, 2006, 02:47 PM
You need to find out if you are getting 24 volts at the white wire in the furnace when the termostat is calling for heat.