I turned on the heat for the first time this season and no heat came out. I checked the furnace and the pilot was out. I lit the pilot and it stays lit (been on for over a day now.) I tried the heat again and still nothing. So, the furnace is getting power, the fan works when "ON." The pilot is still lit, but the burners will not turn on. What could be the problem? Maybe the thermocouple needs to be replaced? Or is that OK, because the pilot stays lit?

I need a little more information. First is anything happening when the unit is calling for heat. It may be as simple as a thermostat not calling. You can take a jumper wire and go from the r to the w terminal on the board. If the furnace lights you have found the problem.

You know, I don't think anything is happening. I don't hear any clicking or anything when I adust the heat up and down. I do here it working when I turn the AC on though. I'll give that a try after work tonight.

I tested the thermostat tonight. I connected the red to the white and nothing happened. I checked the furnace and the pilot was still lit, but the burners did not turn on.

Is there an induced draft motor and does it turn on? I can go through the sequence to try and help you without actually being there.

I have the same problem... pilot is lit, main burners won't turn on. My power venter is on when I turn the thermostats up to draw heat... I can hear the forced water moving through the baseboards... my main thought was maybe my power venter isn't working properly -- kind of sounds like it's not blowing anymore although the motor is kicking on. It's my understanding the gas burners won't come if this is the case. In regards to the jump of the R W terminal, is this what I see on the pilot switch and may allow me to bypass the need for the power venter for a quick test/diagnosis?

I finally got someone to look at the furnace today. He said it's the gas control valve and will cost $600 or $700 to repair. He also said the furnace is about 20 years old and could be replaced for $2850. I chose the repair and I'm hoping the furnace will make it for a while longer.