# Fallen down venting



## Catlin987987 (Nov 12, 2010)

I was called out becuase the new venting( 2 years old) had collaped in the boiler room, When I had gotten there, it had looked like swiss cheese. It was oversized 3 sizes.





























I put it backup until the material I ordered came in. When it did I had hopped up onto the roof(4 story walkup) looked into the vent and found this stuffed in. I think it was 90% blocked.



















After pulling it out, I looked inside the Chimney



















Knowing it would shread the liner I had ordered and might collapse, I decided to rip ot all out, and replace it with bvent. I had opened up the chase and found it was worse then we had thought,














































I will post the finished pics later


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## Redwood (Sep 8, 2008)

So what are you doing about the delayed ignition problem?:whistling2:


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## plbgbiz (Aug 27, 2010)

Redwood said:


> So what are you doing about the delayed ignition problem?:whistling2:


Did oversizing cause the vent pipe to become a combustion chamber? What blew up inside the pipe?


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## Redwood (Sep 8, 2008)

plbgbiz said:


> Did oversizing cause the vent pipe to become a combustion chamber? What blew up inside the pipe?


Somebody sneezed that's fo sho....:yes:


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## Catlin987987 (Nov 12, 2010)

If it was an ignition problem, would every pipe look like that? I think it would only have some sections. The new boilers that were installed are Camus, the old one removed was a Crane with no safetys on the main burner. The damage was throughout the entire venting system, I was thinking that the damage was from heat stress and with weak points were where they are snapped together.


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## Redwood (Sep 8, 2008)

Trust me...

There was a boom....:yes:

Not that I have ever seen this before or, nothing....:yes:

Your blockage looks like the inside of a double wall where it went through a roof penetration...

Was the cap missing?:laughing:


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## Protech (Sep 22, 2008)

You ever see that happen on a condensing commercial heater with pvc fan forced venting? Sounds like a cannon firing. I cut one oen once and when it fired, the lack of back pressure caused years of rust buildup in the combustion chamber to come shooting out like a shot gun. The vent was vertical where I had cut into it so it was raining rust flakes in the boiler room :laughing:



Redwood said:


> So what are you doing about the delayed ignition problem?:whistling2:


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## Tommy plumber (Feb 19, 2010)

If it's oversized (3) sizes as you say, then you have a cold somewhat damp vent not getting hot enough to burn off the condensation. That would explain the corrosion.

As for the evidence of explosions, somehow combustible vapors are getting in to the vent.


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## Redwood (Sep 8, 2008)

I think the most fun I ever had with one going pop was a 400,000 btu/hr burner I had been called to work on that was firing into a tube on a piece of industrial equipment. This was the most temperamental SOB I have ever worked on, and from what I gather it hadn't run right from the day it was installed. Just a poor design IMHO that the customer should have told them to rip it back out and take it with them on the initial installation.

I played around with this unit way longer than I wanted to and literally after playing with it for about a day and a half I got it to where I felt good about the set up and would turn my back on it...

A couple of years later they called me up they were planning on moving the equipment to a different location inside their facility and wanted me to assist them with the move...:laughing:

I told them that was the last piece of equipment they should ever consider moving and that they really should consider junking it and getting a better piece of equipment. I also told them I had no interest in assisting them with moving it and working on it.:whistling2:

Evidently they found a sucker because the next time I saw this unit I was responding there as a firefighter after something blew up. It had been moved and I guess someone didn't manage to find the sweet set up....:laughing:

Yea there was a lot of tin laying around all in funny shapes like the stuff pictured in this thread...

But what would I know....:whistling2:


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## Catlin987987 (Nov 12, 2010)

Customer had thier enginer come out and hw said it was not an explosion, it was a venting system not supported, collapsing and plugging the chiminy, thus causing it to overheat and warp at some places.


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