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Whose Double Wall Indirects are you using?

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The Steam Whisperer
The Steam Whisperer Member Posts: 1,218
We use these mainly in 6 flats and they need to be double wall (Illinois plumbing code). I was using HTP Superstore stainless units , but HTP has stopped producing these double wall models. The 80 gallon units seem to work well with the steam boiler providing hot water.
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Comments

  • Alan (California Radiant) Forbes
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    Mercifully, the UPC dropped their double-wall requirement about 10 years ago. We were using Superstore’s and a few Amtrol’s. 
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • jumper
    jumper Member Posts: 2,306
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    Mercifully, the UPC dropped their double-wall requirement about 10 years ago. We were using Superstore’s and a few Amtrol’s. 

    I didn't know that. Before double wall was coded in in the seventies I never heard of anybody harmed by water contaminated with steam or refrigerant.

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,075
    edited May 2022
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    I didn't know that. Before double wall was coded in in the seventies I never heard of anybody harmed by water contaminated with steam or refrigerant.
    I think they were more concerned about chemicals added to the boiler water getting into the domestic water system.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    mattmia2
  • Alan (California Radiant) Forbes
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    I just noticed that Laars has double-wall indirects.

    https://www.laars.com/images/uploads/products/11027E-NH.pdf

    They also have single-wall, stainless steel models, but I don't remember them being mentioned here on HeatingHelp. Has anyone ever installed one?

    Their MiniTherm boilers have been redesigned and are now JX models; the 125K and larger come with low-loss headers. Pretty much the same design as their JVS models. I've come around to liking these boilers; many in my area are still going strong after 20+ years and they are comparatively easy to service.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab