I had the limit censor go bad on the exhaust fan due to a leak in the exhaust condensation drain tube. I ordered a replacement part and tried to bypass the sensor by closing the circuit. This did eliminate the error condition for open limit circuit but now I am getting a "false flame or gas valve relay shorted" code from the circuit board. I have read several post and I have cleanded the flame sensor and still nothing.

I opened the burner area and started the unit again, the ignitor is not turning on when I power it up and I don't see any pilot, I am assuming I shouldn't as there is an ignitor, and I don't know what I should check next. Help!

I think I fixed the problem. I was just not waiting long enough for the zoning unit to turn the furnace on. All seams well now. Thanks.

Patience is a virtue as you have just found out. At least it was a nice cheap fix for once.

I have a pilotless furnace . My board has 2 lights 1 red 1 yellow . My furnace is running once after I turn the gas v off for 5 minutes . But won't come on again when needed . My yellow is flashing continuously indicating false flame relay short , where is my flame sencor ?