Bryant furnace problem

[fineshade]

I have a 1994 Bryant gas furnace mod 383Kav that is having intermitent problems. It can work fine for a whole day or maybe two then one day when the t-stat calls for heat it comes on okay until the burner lights. It will stay lit for about 15 sec then I hear a click like a switch closing and the burner goes out. The blower will come on to cool down then it will recycle and start up again and usually work ok. It might not do it again for 10 to 15 cycles then it happens again.
I have replaced the t-stat and cleaned the flame sensor, checked all connectors on the control panel but problem still exists. I had a heating tech spend over an hour checking it out and he is at a loss. I read the trouble code. got a 12 (blower on after power up) but that is not the case. The blower does not come on until the gas is shut off to the burner.
Can anyone shed any light on this for me?
Thank You

[HayZee518]

I don't know why people automatically go to the thermostat and replace it when a furnace don't kick in even though they hear a relay kick in when they put the thermostat up. if you have a working diagram of the furnace, you have an accurate troubleshooting guide right in front of you. See what's supposed to happen before you go to the expense of a thermostat, then find out the old stat was perfectly good. check the thermopile generator or the flame sense cicuitry on the main board.

[paul52446m]

I have a 1994 Bryant gas furnace mod 383Kav that is having intermitent problems. It can work fine for a whole day or maybe two then one day when the t-stat calls for heat it comes on okay until the burner lights. It will stay lit for about 15 sec then I hear a click like a switch closing and the burner goes out. The blower will come on to cool down then it will recycle and start up again and usually work ok. It might not do it again for 10 to 15 cycles then it happens again.
I have replaced the t-stat and cleaned the flame sensor, checked all connectors on the control panel but problem still exists. I had a heating tech spend over an hour checking it out and he is at a loss. I read the trouble code. got a 12 (blower on after power up) but that is not the case. The blower does not come on until the gas is shut off to the burner.
Can anyone shed any light on this for me?
Thank You

This can be hard to find this problem. You would have to be right there to test when it happens. Usually flame rod drops out faster than that. Make sure burners are clean and the flame is hitting the flame rod.
Check your burner box for any air leaks. Check all hoses to make sure you don't have a little hair line crack in the hose. It does,t take much to make a pressure switch lose pressure on stop the burner. Take hoses off that are going to pressure switch and make sure there is no water in the hoses. Make sure drain lines are open and not holding any water back. It could be the board itself making this happen from flame rod response reading. Later Paul

[fineshade]

Bryant furnace problem

Paul, thanks for the reply
There is no AC on this unit so no water to get into anything.
I have cleaned the burner tubes and while watching the flame there there are no leaks in the heat exchanger. The flame is fully covering the flame senser. I have received an email suggesting I check the Thermopile generator and the flame sense circuitry on the main board. What is your thoughts on that?

[paul52446m]

Paul, thanks for the reply
There is no AC on this unit so no water to get into anything.
I have cleaned the burner tubes and while watching the flame there there are no leaks in the heat exchanger. The flame is fully covering the flame senser. I have received an email suggesting I check the Thermopile generator and the flame sense circuitry on the main board. What is your thoughts on that?

I think you have a glow bar to lite your burners and a flame rod, so you don't have a Thermopile generator. As far as checking the flame sense circuitry.I don't
think you have a tester that will test milliamp's. You still can get moisture in a tubing hose, so take them off and check them and also check for cracks in the hoses. Later Paul

[fineshade]

Bryant Furnace problem

Paul,
Everything is checking out ok. No water, no cracks and it has been running fine for two days but one time this morning it shut down.
I have contacted Bryant about the problem. They are contacting the technician who I had work on it and will be getting back to him and me with what they think it is.
If you come up with any more ideas I would like to hear them
thank you for your input

[paul52446m]

Paul,
Everything is checking out ok. No water, no cracks and it has been running fine for two days but one time this morning it shut down.
I have contacted Bryant about the problem. They are contacting the technician who I had work on it and will be getting back to him and me with what they think it is.
If you come up with any more ideas I would like to hear them
thank you for your input

Like i said before this can be hard to find the problem. It could be that the electronic board is not sensing the flame response at times? I had one like yours
that i was out on 5 times and i finally had it mess up when i was there, the gas
regulator out side was sticking and would not open fast enough so it just flat run out of gas, then pop right back. The furnace was the only thing on gas in that home.. I would bet that they will end up changing the board. It could be a pressure switch that is getting week so some times it will not stay made.
Let me know what they find. Paul

[fineshade]

Bryant furnace problem

Paul,
Just had a Bryant rep here and found the problem to be the circuit board. It seems the contacts on the board that all of the wiring connect to go bad and come loose over time. Normally they expect the boards to only last 6 to 8 years.
Since this one is the original it did well to last 15 years. I think we have decided to look into a new furnace. The board was over $400.00 installed and with the age of the furnace we decided to opt for a new unit.
Thank you for all of your input.

[paul52446m]

Paul,
Just had a Bryant rep here and found the problem to be the circuit board. It seems the contacts on the board that all of the wiring connect to go bad and come loose over time. Normally they expect the boards to only last 6 to 8 years.
Since this one is the original it did well to last 15 years. I think we have decided to look into a new furnace. The board was over $400.00 installed and with the age of the furnace we decided to opt for a new unit.
Thank you for all of your input.

I am glad you found out what was wrong. Thats good mark up for a $120.00
board and 1/2 hrs work. Later Paul

[irishgator]

Similar Issue!

I am having a similar issue to what is being stated here. Same Model number Bryant unit. I don't have any diagnoses done at this stage, but do know that I have seen codes 13, 33, 34.

Does this provide any more information to be able to diagnose, or should I just call someone?

Any recommendations on good Bryant service in Canton, MI?

Recommendations on what repairs are worthwhile vs. replacement?

The house was built in 1997...

[paul52446m]

I am having a similar issue to what is being stated here. Same Model number Bryant unit. I don't have any diagnoses done at this stage, but do know that I have seen codes 13, 33, 34.

Does this provide any more information to be able to diagnose, or should I just call someone?

Any recommendations on good Bryant service in Canton, MI?

Recommendations on what repairs are worthwhile vs. replacement?

The house was built in 1997...

There is no way that i have manuals and electric diagrams for all the furnaces
out there, so i don't know what codes 13-33-and 34 are Things that can make a burner go out right after it fires, Flame rod needs cleaning, bad or shorted wire from flame rod to brain box, pressure switch not staying made,
brain box getting bad, gas valve going bad, sticking. Any one of the safety
switches getting bad contact points. There is so many things that can cause
this. this is why even a good tech man has trouble finding
what is wrong unless is messes up while he is there and even then some times you only have seconds to test it before it resets. The code numbers
are just a rough guide to help a tech, and sometimes that are no help. later paul