Here is what you can do,

On the furnace their is a circuit board in the blower section, you can try to get to that and jumper the R terminal to the W terminal that will simulate what the thermostat does but we are eliminating the wiring and the thermostat from the equation. If the vent motor starts then its wiring /stat problem. If it doesn't then either the vent motor or the circuit board has failed, let me know what happens. ( you have to push the door safety switch in to test this )

Thanks

Mark

Hi,

OK then we need to see if the same thing happens when the thermostat is set to heat, if not then its a thermostat or wiring problem, let me know.

Thanks

Mark

Hi,

OK, I would say you have more than one problem, the thermostat should just duplicate what the jumper did, which was start the vent motor. The other problem is that once the vent motor starts the ignition sequence should continue on to lighting off the main burner. If you leave the jumper on will the heat start ?

Next thing you want to do is remove the front of the thermostat and jump the R and W there, let me know.

Thanks

Mark

Thanks

Mark

Hi,

OK seems like the thermostat is the problem again. What brand and model is it ?

Thanks

Mark