Pressure Switch Error

[Gerber]

Comfortmaker was giving pressure switch stuck open error (low). Checked inducer, pulling 2.5", switch closes at 1.5 no problems there. Checked drains and hoses, all clear. By passed pressure switch and furnace fired. Now furnace fired 6 times in a row, no errors. I'm thinking bad pressure switch may be sticking, but I always hate replacing a pressure switch without any other indicators so thought I would see if there were any other opinions. M# c9mpt100j16b1

[johnbeck1000]

restart the furnace, remove the wires from the pressure switch and put your ohm meter on it, make sure its close to zero when closed. sometimes they can also close to quickly but i'm not sure of that pertains to comfort maker

[Gerber]

Thank you, if it were to read higher ohms, would that indicate a problem with the pressure switch?

[Mustafatel]

HE WANT YOU TO USE THE OHM METER TO CHECK WHEN IT WILL TURN ON AND OFF.

[johnbeck1000]

I've seen them have ohms in the hundreds and that becomes a voltage block, so the board doesn't get a full 24 volts back to the board.
I'm assuming you are working on a condensing furnace. These furnaces have a knack for the pressure switch tubes getting water in them which corrode the contacts in the switch.

I don't like to see anything other than 0.0-0.3 on a switch, that's my personal preference though

[Gerber]

Thanks for the advice, I appreciate it.