Gas and Oil Home Heating Furnaces - Bad pressure switch?

I have a 4-year-old Gibson RC100-16B furnace. Blink code indicates pressure switch stuck open (2 blinks)...combustion air intake motor/fan are running fine, yet when I remove the leads from the pressure switch and wire them together (bypassing the switch), I still get the same 2-blink code. :confused:

I was going to just go buy a new pressure switch and install it, but now I'm not so sure? It's cold in here... :)

Any help is greatly appreciated. Thanks in advance,
~Ryan in Western PA

Have you taken the hose off and suck on the hose to the preassure switch in and out?

And also make sure the hose port is clear. You went outside and do feel air blowing out of the exhaust pipe?

Thanks for the reply, J. I didn't want to blow into the hoses or anything for fear of breaking the diaphragm in the pressure switch...but I did verify the combustion air is being pulled into the intake port and blowing out of the exhaust port.

Later, at the advice of an electrical engineer friend, I tried powering the furnace up WITHOUT the pressure switch leads wired together, and then carefully connecting them together (via a short paperclip "jumper") after the combustion air fan was allowed to run for about 10 seconds. Sure enough, the LED on the board stayed lit, and startup continued. So I think that verifies the pressure switch is junk.

Hopefully that will be useful information for anyone else finding themselves in the same boat.
:beers:

Out of curiousity, how many wires were on your pressure switch?

Mine had just 2 leads. I've installed the replacement, and everything is fine now. I did have the hoses reversed at first though, which gave me a "pressure switch stuck closed" code of 3 blinks.