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Burnham MegaSteam MST513 piping dimensions?

Rusty2
Rusty2 Member Posts: 32
The MegaSteam Technical Information page lists Dimension "A" for a MST513 as 22 5/8". But the Installation Instructions list Dimension "A" as 28 5/8". Does anyone know this dimension for a 513?
Also does anyone know the center to center distance between the 2 steam take off ports/pipes? Rather than calculate if it's 22 5/8" or 28 5/8" minus (5 11/16" + 4 9/16").
Even better than this, since my drop header is using 3" pipe, what length 3" nipple (without using a union) did you use between the two take offs? Thanks

Comments

  • Steamhead
    Steamhead Member Posts: 15,754
    edited July 2022
    The 28-5/8" is the depth, front to back, of the boiler minus the burner and steam trim.

    Not sure where 22-5/8" comes from on the 513- that's the depth of the 288 and 396.

    I don't remember the nipple length between the steam outlets. But you know you'll need two 3x2" tees, so just get them and lay them out in position, then take your measurement.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
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  • Rusty2
    Rusty2 Member Posts: 32
    Thanks Steamhead. I called US Boiler. That dimension "A" on their MegaSteam Technical Information page was wrong for all MST models. It's not 22 5/8" for a 513. The Installation Instructions have the correct measurement which is 28 5/8". I did the math and calculated that I would need a 3" x 15" nipple between the 3" x 2" Tees for the take offs. This is not using a union and 2 nipples as shown in the near boiler piping kit. Thanks again for your reply.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,097
    edited July 2022
    @Rusty2

    Just my opinion which others may not agree with.

    When you make up the two tees with the 15" nipple you have two threads to work with to get your center-to-center dimension. With the tolerances of the fittings available today, China fittings and depending how the 3" threads are cut on the nipple I would use a union or coupling to make this up. Gives you 4 threads to work with instead of two and IMHO gives you a better chance of hitting your dimension without having fittings overtightened or loose.

    Fittings don't always make in the amount given in the "book" 3" is 1 1/6" as I recall. And even the "book" dimension depends on whose book you look in.

    Plus, you may be able to buy the shorter nipples you need rather than cutting them or having them made
  • Rusty2
    Rusty2 Member Posts: 32
    Thanks Ed. I was counting on the forgiveness of the swing joints. However having someone thread a 3" nipple seems to have become ridiculously expensive these days. You know, the supply chain for the pipe threader that they've owned for the last 20 years suddenly has a link missing. It's actually cheaper to buy a Ward 3" union and 2 shorter nipples. Maybe there's still someone out there who will make a 3" x 15" nipple for a reasonable price.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 13,097
    edited July 2022
    @Rusty2

    I know some will say "it doesn't look right" to have an extra fitting. But it's a dumb piece of pipe. Swing joint's will help.

    You may be able to find a supply house that can thread it. Nothing is cheap anymore

    2 3x 7" nipples and a coupling should work
  • Rusty2
    Rusty2 Member Posts: 32
    Thanks Ed. I'll probably go that route. It's going to be covered with insulation anyway.