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Is this bad (pics)

Dave Merklein
Dave Merklein Member Posts: 61
My vent pipe is reduced from 7 in to 6in. Is this CO poisoning waiting to happen???


  • Mark Eatherton1
    Mark Eatherton1 Member Posts: 2,542
    It wouldn't meet code in my area...

    The UMC allows for a one pipe size reduction, provided that there is only one appliance being served by the stack, and the stack height is such that it can adequately handle the BTUH of the connected appliance.

    Based on that photo, it would appear that there are two appliances being served by that stack. Looks pretty new. Any chance of getting the original contractor back in there to make it right?

    It could cause some spilling of flue products...

  • Dave Merklein
    Dave Merklein Member Posts: 61

    I hope I can get the contractor back in. the problem is the chimney liner is a year old and the boiler is less than a year. It was inspected by the city inspector and he didnt say a thing. he made them correct a diferent minor prob. but no mention of this situation. I have been told I need either a smaller boiler or a larger liner.
  • Mark Eatherton1
    Mark Eatherton1 Member Posts: 2,542
    I agree...

    Are you sure your boiler isn't oversized? That is a steam boiler is it not? Have you done an EDR survey?

    Sometimes (in most cases) a larger chimney liner is out of the question due to available apperture.

    Good Luck.

    BTW, I wouldn't call the city inspoector back in. He has the power to shut you down, even if he DID approve it the first time around.

    If the chimney is real tall, you probably have excess draft working in your favor anyway, but there is no right way to do things wrong. Get them back to address the situation.

    If it were my company that had made a mistake like that, we'd eat it.

  • Dave Merklein
    Dave Merklein Member Posts: 61

    I believe the boiler may be oversized and the inspector was notified but I have not heard back from them yet. and yes it is steam.
  • Dave Merklein
    Dave Merklein Member Posts: 61

    Inspector returns on friday
  • hr
    hr Member Posts: 6,106
    Check with the sizing

    requirements in the latest NFPA 54 National Fuel Gas Codebook. There are some accepted alternate methods allowed, for downsizing but it takes some reading and math calcs to figure out.

    The local inspector should be able to confirm your calcs.

    Then again, it depends on which codebook year your AHJ is using.

    Valve tag looks familiar :)

    hot rod

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  • Boilerpro_3
    Boilerpro_3 Member Posts: 1,231
    Mark E. et el Capacity of vent connectors

    I pulled out my Metalbestos vent sizing info and could not find any limitation on reduction of vent connectors from the size of the draft hood outlet other than it is limited to two sizes on smaller vents and one on larger vents. As long as the connector has adequete capacity according to the tables, it it considered acceptable.

    It really is frustrating to see huge differences in venting requirements from one "authority" to another. It just doesn't make much sense... it almost seems as though some requirments are decided without any testing.

    Sign me confused

This discussion has been closed.