Not sure the brand.. When I have the thermostat call for heat the vent blower and the blower both come on and there is no glow.. I have tested and bypassed the limit switches and that doesn't fix the problem. Now the diagnoses light flashes 4 times which is supposed to mean that there is an open limit switch ( so much for the diagnosis light ) .. I did unplug one wire at a time going to each limit switch according to the wiring and tested each connection for voltage and I traced the voltage all the way to the high limit switch and lost voltage when I connected the output wire to the high limit switch. With the input wire is connected and the output wire disconnected I have 24 volts once I connect the output wire I lost voltage. Does that mean the board is bad ??

T-Top

Are you checking voltage from common to each side of the limit switches?

onefleshforlife

Yes I am...

eschuen

put a jumper across the high limit and see if the ignitor works

onefleshforlife

Thanks I tried that didn't work also tried jumping all switches all to no avail..

T-Top

Did you check to see if you have a 115v going to the glow coil after the inducer motor starts. Just making sure you dont have a hot surface ignitor burnt out and the furnace is out on flame failure. one more question, is the pressure switch closing after the inducer motor starts?

onefleshforlife

Thanks .. I have no voltage at the ignitor and the inducer is working fine and I also bypassed it with a jumper still nothing..

T-Top

Did the pressure switch close after the inducer motor started. At idle the pressure switch is open the inducer motor closes the pressure switch.

onefleshforlife

Yes it works fine However there is no voltage supplied to the inducer... If I jumped the inducer shouldn't it be the same as the inducer motor closing the switch..