After discovering my furnace was giving an error code of 2 blinks, saying the pressure switch is open with inducer on, I replaced the pressure switch. I checked all drains, intake and exhaust outlet for clogs or leaks and nothing, yet it still won't start? I have even gone as far as to remove the inducer motor, when off I noticed the plastic ring between it and where it mounts had signs of dry rot, with an edge of it even crumbled away. My question is about that ring. Does that connection have to be air tight in order to build enough pressure to apply the pressure switch? Any other leads or ideas would also be appreciated, thanks JForristal