# Bryant Code 31



## wrfregm (Dec 27, 2006)

Hi,
I have a 10 yr old Bryant gas furnace that continuously is giving a code 31. According to the chart on the furnace this is an issue with the pressure switch. I purchased a new pressure switch and that did not solve the issue. I also cleaned the flame sensor. I next removed the inducer blower case and cleaned it and resealed it. While I had the lines off I removed the condensation trap and cleaned it and the hoses attached to it. It was really gunked up in the hoses and the trap. Since then the furnace ran for two days with no issues. Now I have the same code flashing again. When the furnace does run it operates normally. The flame is blue the pilot lights I hear the gas valve turn on. When the furnace shows code 31 I can reset the circuit breaker and it will run again for a few cycles. Sometimes when resetting it takes two or three times to get it to clear and start. Any help would be appreciated.

Product # 350MAV0360ACKA
Model # 350MAV036060
Serial # 3495A02874


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## #CARRIERMAN (Oct 18, 2006)

Hi wrfregm

Your furnace may be at the age it needs the heat exchanger cleaned. This is a pretty detailed procedure. you will have to remove the draft inducer clear down to the collector box. Then the heat exchanger has to be cleaned with a mixture of bleach and water. My reccomendation is to call a reputable company to do this for you. If you lived in my area, I would love to show you how its done.

Good luck 
Rusty


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## wrfregm (Dec 27, 2006)

Hi CARRIERMAN, 
Thanks for the reply!! Too bad you are not from my area - I am determined to fix this thing...


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## Aceinstaller (Feb 11, 2006)

bleach and water?

where did you learn that one?

a customer would end up paying less for an exchanger replacement, due to the time it would take to dissasemble the unit and clean the exchangers thoroughly with a liquid solution.

most soot in a heat exchanger can be cleaned by removing the inducer housingand the plate that it mounts to, then some high pressure co2 usually does the trick.

but I have a feeling that all of this is not necessary to fix the problem at hand.

I suggest ensuring that the port from the inducer housing where your pressure switch hose connects is clear of debris.

Then remove and clean all of the drain hoses in the unit that lead to the trap. (if the water can't drain out of the inducer housing, it will slow the inducer down and the air switch wont make)

But most importantly, take a good look at your vent pipe. hopefully it is exposed. first check at the exterior of the home, ensuring that there are no birdnests or leftover waspsnests from the summer. then, inside it should be pitched about 1/16 of an inch per foot sloping down towards the furnace, with no sags causing condensate to trap in the pipe restricting the airflow.

post back with your findings

Ace


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## acefurnacefixer (Nov 24, 2006)

I also wouldent rule out a circut board giving a false code. What needs to be done is a magnehelic needs to be put on the unit when its acting up. It will show if the draft motor is even pulling hard enough to make the switch.

Around the time that your unit was being made carrier was putting out some units with really crappy drain hoses on them, the hose would colaspe and give a pressure switch code.So check them to.........if they seem squishey then replace them also.

I would NOT put bleach into your secondary heat exchanger, i am about 99% sure you would void your lifetime warrentee from carrier. Bleach is perfectly fine to use for the trap and lines leading to the trap as well as your dirty socks and underwear.......but not for secondary heat exchangers.


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## #CARRIERMAN (Oct 18, 2006)

Hi guys

Get a hold of a Carrier tech manual, inside of it will be the cleaning procedures. If you find I am wrong, than I will admit to it. But I know I am right, we just had a tech training from Carrier. But acefurnacefixer is right about the magnehelic. This is the only true way to determine what I am talking about.

Good luck
Rusty


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## acefurnacefixer (Nov 24, 2006)

#CARRIERMAN said:


> Hi guys
> 
> Get a hold of a Carrier tech manual, inside of it will be the cleaning procedures. If you find I am wrong, than I will admit to it. But I know I am right, we just had a tech training from Carrier. But acefurnacefixer is right about the magnehelic. This is the only true way to determine what I am talking about.
> 
> ...


 
You had to know that i would do it..............I called Carrier in Livonia Mi. Spoke with the head of the tech and service and straight out of the service instruction for condensing furnaces, "use water only", "if water will not free any forgien matter then the heat exchanger is concidered to have failed and both primary and secondary units should be changed ."

Sorry Rusty I know you mean well.


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## #CARRIERMAN (Oct 18, 2006)

Hi guys

I stand corrected, this is what they are reccomending for cleaning of algae. I will get in touch with our Carrier trainer and find out the scoop.

Rusty


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## wrfregm (Dec 27, 2006)

Aceinstaller said:


> bleach and water?
> 
> where did you learn that one?
> 
> ...


Hi Ace,
Checked the inducer port-it is clear.
All drain hoses are clear of debris.
Vent pipe on exterior is clear of debris.
All pipes appear to be sloped and I see no sagging.
The drain hose is soft and may be too weak allowing it to be pinched. Will find a new one.
I noticed the silicone hoses appear to be hardening in the area of the back of the inducer. I stopped a Home Depot thinking I may be able to buy some new hoses-no such luck.
I have never used a magnehelic gauge I will have to see if I can find one at a rental store or buy one outright.
This is frustrating-but challenging!! The wife has been understanding which is a help. (even when it was 66 deg. in the morning)
Thanks, Wade


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## #CARRIERMAN (Oct 18, 2006)

Hi wfregm

It looks like you found your information with aceinstaller. I am going to back away and let him finish helping you. If you need to verify anything I have put in my post, go to your owners manual and look in the back. If you need any further assistance from me, leave me a private message and I will get back in touch with you. There is a hose kit for that furnace, I am sure ace can find the part # for you. I didn't notice where you said it was sooted up, if you replace that heat exchanger and send it in for warranty and its not sooted. That heat exchanger is about $800.00, but judging by the information given, aceinstaller would have know that.

Good luck
Rusty


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## wrfregm (Dec 27, 2006)

#CARRIERMAN said:


> Hi wfregm
> 
> It looks like you found your information with aceinstaller. I am going to back away and let him finish helping you. If you need to verify anything I have put in my post, go to your owners manual and look in the back. If you need any further assistance from me, leave me a private message and I will get back in touch with you. There is a hose kit for that furnace, I am sure ace can find the part # for you. I didn't notice where you said it was sooted up, if you replace that heat exchanger and send it in for warranty and its not sooted. That heat exchanger is about $800.00, but judging by the information given, aceinstaller would have know that.
> 
> ...


#CARRIERMAN - Unfortunately, I am unable to PM you as I do not have 20 posts yet. I also cannot e-mail you as your settings to do not allow me to contact you. If you would not mind you can e-mail me at [email protected] as I appreciate your input.
Thanks, Wade


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## trollmastergeneral (Dec 19, 2006)

was there any water in the furnace a lot of carrier unts had a issue with the secondaire heat exchanger rotting out normaly you will find water and rust inside the doors of furnace.


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## trollmastergeneral (Dec 19, 2006)

let me clarify i meant the secondaire heat exchanger cover i dont want to be todays " whiping post ":thumbsup:


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## #CARRIERMAN (Oct 18, 2006)

Hi wrfegm & trollmaster

The secondary heat exchanger in the newer Carrier, Bryant, and Payne 90% units are a coated stainless steel heat exchanger. I have never seen one fail, but that doesn't mean it cant. What I was trying to get through to wrfegm was to have a professional come out and perform a cleaning of the secondary heat exchanger. But I guess its easier to criticize some one for advise than it is to just help them along. I am a master tech and dont mind giving away the information. But when its taken out of context, I have to ask myself why bother. Any way get a professional out and he will be able to fix the problem. It takes roughly an hour to do this cleaning. The hose kit is only about $30.00 and can be replaced at the time of the service.

Good luck
Rusty


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## acefurnacefixer (Nov 24, 2006)

#CARRIERMAN said:


> Hi wrfegm & trollmaster
> 
> The secondary heat exchanger in the newer Carrier, Bryant, and Payne 90% units are a coated stainless steel heat exchanger. I have never seen one fail, but that doesn't mean it cant. What I was trying to get through to wrfegm was to have a professional come out and perform a cleaning of the secondary heat exchanger. *But I guess its easier to criticize some one for advise than it is to just help them along.* I am a master tech and dont mind giving away the information. But when its taken out of context, I have to ask myself why bother. Any way get a professional out and he will be able to fix the problem. It takes roughly an hour to do this cleaning. The hose kit is only about $30.00 and can be replaced at the time of the service.
> 
> ...


 
If you are refering to the bleach issue, then I dont see how thats a *CRITICIZE*, YOU SAID AND i'LL quote you


> Get a hold of a Carrier tech manual, inside of it will be the cleaning procedures. If you find I am wrong, than I will admit to it. But I know I am right


Well russ as it turned out ,i called carrier (I got tech support in Livonia on speed dial) and they proved you wrong (big surprise:no: ) Carriers policy is that if the heatexchanger becomes plugged to the point that it cannot be cleaned with hot water, then the heat exchanger is concidered to have failed and should be replaced under the carrier limmited lifetime warrenty. I just want to know why we have to continually beat a dead horse?


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## trollmastergeneral (Dec 19, 2006)

Well I thought older units did not have a stainless steel cover.I could be wrong time flys by fast in the heating buisness.Maybe it was longer ago than that.I was only trying to added to the posible problems that the furnace may have had,not trying to say this was the answer.sounds like a lot of good techs in here.:thumbup:


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## markebenson (Dec 29, 2010)

*I have a code 31 too.*

I have a code 31 on my furnace. It starts then stops after several seconds. This is not a pressure switch related issue. The pressure switch it not open when the unit fails. I even held it in manually for a few minutes and the unit still starts and stops on its own. Any Advice?


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## markebenson (Dec 29, 2010)

K it ended up being the control pcb. I got one on ebay for $55. They have many more available if anyone else gets the same problem. 

EVERYONE HERE HAS BEEN TALKING ABOUT THE PRESSURE SWITCH RELATED ISSUES. Watch the pressure switch to see if it deactivates before the unit fails. If the pressure swich cuts off AFTER AND NOT BEFORE the fan, furnace, etc cuts off, there is really no other components I see that can cause this problem other than the pcb. It fixed my problem!


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