I have a Concord 90+ efficiency furnace installed in my new house built 2.5yrs ago. What initially happened was it would start then shut down (pressure switch closed with inducer off), then a relay would click repeatedly. Prior to that occurring, the furnace would kick out intermittently and not restart (I would reset the furnace then turn it back on and it would be fine). I found a small amount of water in the drain hose from the inducer motor, drained it and cleared it, I can blow air through the hose.

I ended up replacing the pressure switch and control board, the clicking stopped however, the furnace will start, fire and then shut down (pressure switch closed with inducer off).

Other things I've done:

Placed a shop vac on the end of the exhaust/intake which vents out the side of my house, when I placed the shop vac on one, I could feel air pulled in on the opposite pipe.

Are there any other things I can try before calling a repair person? I don't want to spend hundreds if I don't have to.

Thanks.