no sweat, i had a brainfart, didnt comprehend what you were saying.
very very rare but it can happen where a spider nest causes irratic operation, usually they create conplete blockage.
id still look for whats causing the disruption in the fire tetrahedron. we know there is fuel, oxygen and heat.
the fourth part of the fire tetrahedron specificaly is reaction. in this context it involves the correct mixing of the first three.
the OP needs to look for whats keeping that from happening
my boss thinks its possible to repeal the laws of physics
I had a Bryant once that had a spider web in the cross over wings/tubes. They were cleaned, they looked fine. But if you blew through it hard enough the web popped up like a valve. it would NOT do it all the time.
To clean the cross overs I use a small triangular piece of 30ga sheet metal or if the cross overs are wide enough I use a fingernail file. (Ya if my wife asks, I have no idea how that got in my tool bag )
who knows, just a suggestion, good luck
Of course I talk to myself
sometimes I need expert advice
Thanks for all the replies fellas.
And like I said... after the first series of the unit not firing properly I dismantled the manifold, removed and blew through the orifices and manifold multiple times and found no sort of blockage....
After reassembly, the next cycle fired only one burner again, and after that trial and reset it fired normally (presumably coincidently) after I adjusted the manifold pressure.
So we know I likely didn't clear any debris when I disassembled/reassembled.
It's this series of events that has me confused.
I'm sure there's some explanation....
As far as I know the gentleman hasn't called back in. Who knows if maybe I DID clear some debris and it was finally removed the same cycle as when I adjusted the manifold pressure.
As someone asked before whether or not it was burning normally when it did fire properly.... it all seemed normal up until the single burner firing. Then one of the next cycles (and last before leaving) that did fire "normally" did have some strange ignition like I mentioned before. A delayed, "hard" sort of POOF.... and this was after the gas valve engaged and I could hear gas being released from the manifold for a split second.
Also to mention, during disassembly/reassembly I did adjust the position of the HSI as it was slightly cocked and away from the burner plate.
But, due to that delayed ignition and what was observed I believe the gas valve and manifold is doing its job and this is an issue with the crossover rails and/or flame/gas traveling properly. One way or another.
Now I'm officially bugged and ready to take another wack at this unit....
Yes I believe it does. Interesting to note...
Originally Posted by ch4man
Also to mention, this house was a foreclosure and this is the first winter with the h/o living there. For all we know this was a previous ongoing issue.
My plan of action was to give a call to see if there were any crossover or ignition issue with this unit. Last winter, an unknown defect with a 12 year old Lennox 90%+ had me beating my head against a wall until speaking with a third Lennox rep... haha.
As well as this year with a brand new Lennox 93%.
It gets the best of us.
The thing that has me wondering is the burners all being one assembly when all the Bryants I've seen, including mine, have individual burners. Also for the behavior you describe with burners that appear clean I have taken the tip of a small screwdriver and used it a bit like a prybar in the crossover slot and have broken loose some junk hiding inside there. Just a slight nudge in prying and the slot does'nt grow bigger but just flexes enough to dislodge an obstruction. It's worked for me a lot of times.
This style of unit, as well as the Carrier counterpart all have that single burner assembly I believe? The burner assembly slides into the burner compartment, one end of the manifold slides into a mount on the edge of the burner box and the other end is secured by two screws. The orifices on the manifold is all what keeps the burner assembly secured basically. If that makes sense. Ring a bell?
Originally Posted by Ron
I probably should've paid closer attention to the crossover rail rather than a couple swipes with a wire brush. Once revisited I will surely give the fine-tooth-comb treatment.
I seem to remember from a seminar that you have to make sure the manifold hasn't been twisted off axis. ( if that makes sense) there was a picture where the manifold and burners HAD BEEN REMOVED (caps for empahasis) from the furnace and water was being forced through the manifold to prove everything was lined up.
I love my job, but paydays Thursday
I have seen closed combustion units do this after HSI installed with after market. Box does'nt seal correctly,swirling combustion air disturbs ignition..,flame sensor shuts down! And it too doesnt act up all the time!
The Lennox 90%+ I mentioned above had a similar problem, except it would NOT ignite via the HSI. Could only get it to light manually with open flame. Swirling combustion air...
Originally Posted by Cosmicmuffin
Except this Bryant unit in question is just your run-of-the-mill 80%. I'm wondering if the IDF cooling fan could be creating the issue like someone mentioned above. I'm going to be contacting the distributor/manufacturer to see if there's an issue with this unit and an upgrade kit available.
Put an email address in your profile, or send me an email (address is in my profile), and I will forward back the only bulletin I know of relating to this issue.
Originally Posted by ComfortablyNumb
I don't post technical info in this "OPEN" Tech to Tech Forum.
Instead of learning the tricks of the trade, learn the trade.
Also inspect that the cross over flame is not obstructed
had seen the spider web before was a white web that completly clogged the first tube preventing any gas to HSI. another time had cleaned and brushed burner assembly and still had the problem then removed and blew out with co2 pressure that fixed the problem.
I've ran into this before, and called my service manager for advice. He said to run a razor blade through the crossover tubes, sometimes during original installation or unit manufacture tiny pieces of metal can become lodged in there. Did what he said and the system fired from one burner to the next no problem, and as far as I'm aware, the customer hasn't called back.