Bryant 373LAV furnace with Code 31

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The furnace in our attic is just not working and we are out of ideas. We have already replaced the pressure switch, and now it won't even run with us jumping the switch. Found a bird's nest in the vent up to the roof and removed that. (But it was never completely clogged. and that is an exhaust vent, isn't it? It runs to the inducer motor.) We've been advised to clear out the intake to the burner compartment, but can't figure out what or where that is. ANY help would be appreciated.

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Still not working, any help would be great!

I was also told to check the condensate discharge trap. But I think those are only on high-efficiency units?

[hvactech126]

does the inducer run? Have you taken the flue pipe off the furnace to confirm you got everything out of the flue?

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The inducer runs. I took the flue pipe off and even tried running the furnace with the vent disconnected. Still didn't work.

[hvactech126]

the port that the tube hooks to @ the inducer is probably plugged, try to clear it out with a paper clip or small drill bit. or i believe there is a vent blockage switch just above the p/s that may be tripped and cause that code because the orange wire goes through that switch either b4 or after the p/s

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I have tried clearing out that port (another person i heard from called it a "nipple"), so I believe it is clear. I will check to try to find a vent blockage switch.

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Making progress!!!!!!!!! But I still need help!

the port that the tube hooks to @ the inducer is probably plugged, try to clear it out with a paper clip or small drill bit. or i believe there is a vent blockage switch just above the p/s that may be tripped and cause that code because the orange wire goes through that switch either b4 or after the p/s

I bypassed the vent blockage switch and got it to work! Now the question is do I just get a new switch, or can I "untrip" this one? There is a little tab sticking up from it that is very wiggly. Should it lock back into place? I pushed on it pretty hard and nothing happened.

[hvactech126]

you should be able to reset it by pushing in on that tab between the wire terminals, if that does not work, then get a new one, however, I do not recommend running the furnace with any safety device bypassed! Glad you found the problem!

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So far, so good!!!!!!!!

Ok, this is the wife typing. It appears the switch was reset by pushing on it. It's working so far!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

And no, we would NEVER run it without all the safety things in place. We like living. (But it is always good to remind people about safety stuff.)

You guys rock! Thanks for helping us out--you saved us money, and now we both know more about how our furnace works. Hopefully we can use the knowledge to help someone in the future. God bless you all!