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Bryant Plus 90 Problem

4K views 17 replies 5 participants last post by  sixstrings24 
#1 ·
I have a Bryant Plus 90 furnace propane that worked once since I turned it on a few days ago and hasn't since. The fan works and the thermostat works. I get code 31 whenever I attempt to start the furnace. The, for a lack of a better term, "little" blower motor comes on and the LED stays lit for about 30 seconds then blinks. 3 fast 1 slow, code 31. I ran a continuity test on the pressure switch terminals and started out with infinity and resulted in infinity. I then checked the air intake PVC pipe and there is no obstruction. I then pulled all the hoses off and blew through them to find they are clear of debris. I checked the condensation trap...empty. My conclusion is the pressure switch is bad.

Am I wrong in thinking this?
Is there another possibility?
Is there any way I could bypass the pressure switch until the new one arrives?

I live in northern Wisconsin and the nights have been getting pretty cold. I would just like to heat the house up for an hour or two and then shut it off for the night. We have a pretty air tight house so the heat stays for a while. Also our furnace is not within the house itself. It is in the attached pole building.
 
#3 ·
sixstring,

code error 31 indicated faulty high pressure switch. Something is obstructing the vent or the switch might be bad it self. If you are sure that the exhaust vent are not obstructed, then yes you can test the pressure switch by jumping. Turn on heat, and once the induce draft motor (vent motor) starts, immediately jump the two wires together with a jumper wire, you don't have to take the wires off of the switch, just move it out enough to where you can clip your jumper wire.
 
#11 ·
Thank you Mr. HVAC. I just ordered a new one from eBay for $30.00. I should get it by next Tuesday. If that doesn't fix the problem then I will have to remove the vent pipes which will be tough since they are going through the wall. I might just see if I can't get my hands on a plumbers snake and feed it through the pipes to clear any possible obstructions I could not see from looking down the external end of the pipe.

I did run the furnace to heat up the house for about 30 minutes. Nothing seemed to go wrong. I kept a close eye on it and a hand on the propane shut off valve. :thumbup:
 
#14 ·
You're welcome sixstring,

whatever you do, please don't run it using the bypass method. In fact, take off the jumper wire and unplug the furnace so that your family don't accidently turn it on while you are away. Let us know once you install a new. Oh by the new, don't blow into the pressure switch, that will damage the diaphram (sp).
 
#2 ·
make sure tubes to pressure switch and ventor motor have no obsructions.... if you read 24 volts when ventor motor running pressure switch is open ...may be a bad switch may not be ...lots of things can cause a switch not to close.. the info on furnace should tell you what code 31 means .... i forget what i had for breakfast so i cant help with code 31..
 
#6 ·
Thank you!!

Thank you all for the responses. I am about 98% positive the pressure switch is bad. I jumped the leads on the switch and the burner lit up and ran for around 5 minutes until I removed the jumper and the burner shut off. I figure the burners could not stay lit if there was something obstructing the vent pipe which I had already checked previously. This is my first time working on a furnace but the knowledge I gained will help me in the future. Thank you all for the input :thumbsup:.
 
#7 ·
Thank you all for the responses. I am about 98% positive the pressure switch is bad. I jumped the leads on the switch and the burner lit up and ran for around 5 minutes until I removed the jumper and the burner shut off. I figure the burners could not stay lit if there was something obstructing the vent pipe which I had already checked previously. This is my first time working on a furnace but the knowledge I gained will help me in the future. Thank you all for the input :thumbsup:.
It is a very poor idea to run the furnace with the pressure switch jumped.... there could be something in the pipes thats the switchs job... it is probably bad replace it.... and you will find out
 
#18 ·
Thank you all!!!

To all of the people who gave me information and warned me about the danger, I fixed the problem. I received the new pressure switch today that I purchased on eBay for $30.00 and hooked it up. The furnace still gave me a code 31. My next step was to remove the PVC pipe from the induction draft motor and checked it for obstruction. Upon first glance I noticed some feathers coming out with a little water. So I thoroughly checked the pipe to find it was clear. I then stuck my finger into the induction motor housing and sure enough I felt feathers. I grabbed my needle nose pliers and pulled out a bird that had been in there a while. I wanted to get it completely clean so I removed the ID motor and took it outside to pull it apart and clean it out. Once outside I decided not to pull it apart since it was sealed with silicone. I then noticed more feathers further into the housing and sure enough, another bird. I got a little mirror I use for working on cars and stuck it in the housing to make sure there was no other obstruction. It was all clear at this point. I re-installed the ID motor and all the pipes and hoses and electrical connections, fired it up and it works like a charm. Even the ID motor barely makes a sound. Thank you all for the info. I greatly appreciate it. Have a great day.

:thumbup:
 
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