[jimmynac]

Been tring to figure out why the pressure switch keeps shutting down after about two minutes. I checked the flue and all is clear. I bypassed the switch and the system works. I even used a small vacuum and the system kept working. What else can it be?

 

[NickTech]

it could very well be a bad switch who's contacts just won't keep. try measuring the vacuum w/ a digital manometer. see if there is a fluctuation in the pressure to the switch, just to rule out the motor or the flue system itself. if there is no fluctuation in the pressure it is most likely a bad switch. also, check for leaks around the mounting of the draft motor, and the tube to the switch.