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Gas Boiler and Water Heater Flue / Venting

I am a homeowner. I had a new gas boiler put in about 8 years ago and a new gas water heater put in about 2 years ago. Recently I had a plumber in my basement for something unrelated and he noticed all of this and told me the way the flue / venting was done was incorrect (excuse me here if I don't have all of the terminology right). This is a link to a video of what I am asking about: <a href="https://www.dropbox.com/s/0f5cphkzpiulfd4/Video%20Jan%2005%2C%209%2051%2044%20PM.mov">https://www.dropbox.com/s/0f5cphkzpiulfd4/Video%20Jan%2005%2C%209%2051%2044%20PM.mov</a>. It was too hard to get good still pictures; the video shows it better. The boiler has a round 8" diameter sheet metal vent that connects straight into the chimney. There is a 4" diameter round sheet metel vent that connects from the water heat into that 8" vent right before the 8" vent goes in to the chimney. It is about 5' from the connection of the 4" vent into the 8" vent to the water heater. About 2' from the connection of the 4" to the 8", there is a piece in the 4" vent which basically is just hole in the bottom of the 4" vent. It is 3' from this hole in the bottom of the vent (it is actually a sheet metal thing that looks a little like a scoop). I figure this scoop thing is in there to allow some make up air into the vent so a draw can develop to let the hot air rise up and out. And air does draw in at this opening. The water heater has a vent hood. That is the thing the plumber said was wrong. He said it shouldn't have the both the vent hood on top of the water hater and the the scoop thing in the 4" vent line. I don't know how the old water heater was hooked up. Can any of you pros (or knowledgable Wallies) help me sort this out? Should I remove the vent hood from on top of the water heater and just connect the 4" pipe straight to the water heater? Thank you for your help!



  • Jim Davis_3
    Jim Davis_3 Member Posts: 578

    I see you have posted this on another HVAC website also and I am not sure which one you will read first, assuming your not in the hospital yet.  But that extra hole is a horizontal drafthood that is most likely illegal.  It is singly one of the most dangerous drafthoods ever made.  100% of the ones I have tested were causing occupants to get poisoned.  Get someone quick that knows what they are doing to fix it quick.
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