Payne 90 plus furnace no start
You must have your fan switch set to ON on the thermostat instead of Auto if the blower comes on as soon as you close the interlock switch. Did you kill the power at the breaker for 1/2 hour go back and turn on power, then try thermostat to call for heat? Get on cell phone to helper, Turn power on in breaker, have helper turn up stat while you look through observation port of burners, and record what happens, sounds and all. Inducer (little) fan should cut in for a while, then igniter should glow, then you should hear a click, which is solenoid on gas valve. pilot gas should flow and ignite, then burners cut in. In a little while big fan should spin up to blow heat through ductwork. Record what happens then come back.
" A lot of men build things, and a lot of things fall down "