I also have a Lennox G12 furnace. The furnace appears to be working correctly, pilot lights, burner goes on, blower works, etc. I have a service contract on it with a local company. However, the amount of heat it is putting out seems much lower this winter than last. It takes 4-8 hours to heat up a room that took 1-2 hours last year at the same approximate temperature. Is there anything that can be causing this? Thanks.
Hi Guys;
Just a thought that might help with the heat not getting the place as hot as fast as it used to.
Check your ducts for holes, insulation that has come loose, ducts that have come loose at the registers etc.
Tighten them up and then add some insulation over the ducts. Youd be suprised at how toasty you get after that.
Hope this helps. Best; Smitty
that's all taken into consideration "Smithy" but the problem is the main burner is not firing up. OK, the pilot is staying lit that eliminates the millivolt generator which you have pictured. next is to check you are getting 24 volts to the main gas valve which you also have pictured with the yellow and red wires. use a multimeter set for 200 volts and measure the voltage at those terminals when the unit is calling for heat. if you have 24 volts but the solenoid didn't open then replace the gas valve solenoids or the whole valve. shut the gas off before you disconnect any piping.
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