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Water heater exhaust pipe

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frank100
frank100 Member Posts: 24
I recently replaced my water heater and mistakenly bought a tall one , the the exhaust pipe at the chimney side is at the same level as the water heater side. I plan to open a new hole on the chimney to avoid backdraft. I also noticed the pipe has another opening facing down between water heater and chimney, see photo.  Will this opening help the vent or it is totally unnecessary or even worse to leak the co2 to room? Thanks

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  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,157
    edited December 2022
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    That rectangular box is a draft hood. Just a suggestion. I'm not actually sure it is the correct thing to do because the manufacturer has included a draft hood at the outlet of the water heater.

    If you remove the manufacturers draft hood and place vent the elbow directly on the tank, then check the pitch of the vent pipe. If you have at east a 1/4" per foot slope up the the chimney opening, then you may be OK with that. Technically you do not need 2 draft hoods and since the vent connector pipe has a draft hood included, you may be within the specifications of the manufacturer and the applicable code that covers venting.


    As far a Liability is concerned, If there is an issue with Carbon Monoxide or other problems resulting from backdraft or poor draft, an insurance provider may have the ability to deny paying the claim because you did not follow the manufacturers instructions.

    In my own house, with the tools I have to check for proper draft, I might do it. In a customers home, I would put that water heater in my warehouse for another future customer and purchase a shorter water heater for you.

    Mr. Ed

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    pecmsgGGrossjjinri
  • Lance
    Lance Member Posts: 272
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    The best answer I can give you to save your life and home from a potential disaster is get a licensed plumber/gasfitter to install this to code. Unless you don't have home insurance, or care about the warranty, or the risk, it matters to have a legal installation as insurance companies and manufacturers do not cover losses when codes are not followed. The best thing to do is get the lower height heater, use proper vent size per the btuhs and flue, eliminate the old draft hood (oval). maintain fire clearance between the vent connector and combustibles. 6" for what you have, 1" for B-Vent. Test for proper draft and gas pressure per code for compliance. All of this is in the codes and in the manufacturer's instructions. It costs a lifetime to build a human, it takes seconds to kill it. And even if this is done correctly, a poor chimney flue can also be a problem. It also needs to be measured for proper draft. I think modifying the chimney breach is not the way to go here. Good luck and stay safe.
    jjinri
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,157
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    @Lance, I believe the OP stated this is a temporary situation. He is going to put a new opening in the chimney above the existing opening.

    The Question is: Does @frank100 have the expertise to properly place a new chimney crock or chimney opening according to the Standards of the ASTM-C315, NFPA or the other alphabet soup of official regulators, standards and guidelines?

    I have a feeling there is just going to be a sledge hammer and a chisel involved. Hope for the best outcome inside the flue liner (if there is one) and just make it look pretty on the outside. I could be wrong, For all we know Frank is a professional chimney installer and repair person. He just does DIY plumbing for his own home.

    Personally I would go for less masonry work and a shorter water heater.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • pecmsg
    pecmsg Member Posts: 4,916
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    In the 1st picture the plastic escutcheon is already melted. Not a good sign!
    realliveplumber
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,157
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    pecmsg said:

    In the 1st picture the plastic escutcheon is already melted. Not a good sign!

    Probably soldered the Copper x Female adaptor in place (never a good idea). I wonder if he melted the top of the plastic dip tube inside the water heater?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    Larry Weingartenrealliveplumber
  • Long Beach Ed
    Long Beach Ed Member Posts: 1,215
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    I'm with Ed. Remove the manufacturer's draft diverter, and if you have the proper pipe pitch you are good to go. I'd check for CO and check the draft hood for a proper draft under differing conditions.
  • frank100
    frank100 Member Posts: 24
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    Thank you very much for all the comments. Yes, I will need to hire some professional to open a hole on the chimney. 
    EdTheHeaterMan
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,364
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    Hi @frank100 , I was taught by one of the dead men a trick for dealing with lack of height, like you have. I was told to put a vent T on top of the tank where the draft hood would have gone. Put the center of the T on the heater. Then run one side of the T over to the chimney, with a slight up-slope. On the other end, run over to the side of the tank, 90 down and run it down about two feet. This creates a draft hood that basically forces draft to go in the right direction. I'm not suggesting it's code, or that the manufacturers would approve, as it would be called a field modification. Still, it works. In your case, you could extend the square sheet metal down two feet. This would do a similar thing. All that said, ultimately I like the idea better of raising the vent termination into the chimney and using the factory draft hood.

    Yours, Larry
    Long Beach EdMikeAmannEdTheHeaterMan
  • Bob Harper
    Bob Harper Member Posts: 1,044
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    You could do it properly by relining the chimney with a listed liner sized for both the boiler and the WH. Open the breaching so the vent connector manifold attaches to either a tee snout (bull) within 6" of the ceiling or just sweep it into the room. Tees are not required for listed liners per the IRC. Create a manifold by teeing off from the boiler vent connector laterally to the WH or better yet, use a wye with the branch to the WH. All vent connectors must be pitched up towards the chimney 1/4 per LF and have a min. 3 screws per joint equidistantly spaced and supported every 4-6 feet. No screws btw 5-7 O'clock where acidic condensate will eat up cheap electro-plated screws. Also, no seams in this area- keep seams above this level to prevent pooling of acid within the folds of the seams where it can fail unseen until too late. Elbows should be supported vertically and laterally. When you replace that single walled galvanized steel vent connector to the WH, ensure it is sized per the code. For low vent rise, it is usually the next size larger than the draft hood collar. That's why 40 MBH WHs come with a dual 3"/4" draft hood connection- they expect short vent rise because they make WHs too tall because the dopes at the DOE are pushing them to higher efficiencies without regard to combustion safety. No foil tape or anything over vent connectors btw. Replace the draft hood with a bullhead tee with a double acting barometric damper with a spill switch wired to a thermocouple interrupter on the WH gas control. Perform combustion analysis on both appliances and tune as required. This will include considering makeup air. Install low level unlisted CO monitors and that should just about do it. Or, reline to the boiler and install a power vented or tankless WH vented out the sidewall. If you can't get a big enough liner to common vent both appliances, you'll have to do this or resort to an indirect tank. Just because they had the old one connected to the chimney doesn't make it ok.
    While I'm at it, no aluminum beer can liners in chimneys that have ever served oil or coal. The sulfur will eat them up in no time. Use high-grade stainless-steel alloys such as 316L, 316Ti, or AL29-4c.
    HTH,
    Bob
    Long Beach Ed
  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,211
    edited December 2022
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    Yeah. The guys are correct.  Get a pro in there.  Punching a hole properly in to chimney can be difficult.   Those in line draft diverters were in use for many decades but they don't want you to use them anymore- Inspectors will shoot them down.  Mad 🐕 Dog
  • Lance
    Lance Member Posts: 272
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    Just remember all, the life you save may be your own. I had a man in front of a furnace doing a check of operation. When it got real quiet the owner looked into the basement and found him passed out on the floor. Passed out from CO. Saved his life. Vent problem! He didn't have a chance to get his draft test done. We carry CO detectors for personal protection.
  • ChrisJ
    ChrisJ Member Posts: 15,870
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    Lance said:

    Just remember all, the life you save may be your own. I had a man in front of a furnace doing a check of operation. When it got real quiet the owner looked into the basement and found him passed out on the floor. Passed out from CO. Saved his life. Vent problem! He didn't have a chance to get his draft test done. We carry CO detectors for personal protection.

    I'm confused.
    Was that man a "Pro" ?
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment