Nordyne M3R limit switch tripping

[speedbow20]

Hi all,
I have a Nordyne M3R series furnace in my Modular home, it is 5 years old. Last year it kept tripping the limit switch located on the exhaust motor area. I replace the plastic orifice located in the unit and it worked fine. This year, it started tripping it again, I replaced the orifice again, and the limit switch. The switch keeps tripping and i had to remove it from the furnace area so the heat wouldn`t trip it. i know this is a bad idea, but I needed heat at that moment. The motor on the exhaust fan is exposed in a way i can touch it. it gets hotter than hell, almost too hot to touch, the PVC exhaust pipe gets pretty war too. Any ideas why it might be tripping the switch? I`m going to climb up on the roof tomorrow and see if the exhaust pipe is clogged.

[beenthere]

You need a tech to check out whats wrong. before you burn down your place.

[HVAC/Stud]

Call tech support, check correct limit switch degree.

Stud

[heaterman]

You have a dangerous condition and need to have it remedied immediately. Messing with a safety devise is not the smartest thing to do. It's there to prevent what ever is occuring in your furnace and you have eliminated that safe guard.