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EDR boiler size round up or round down

GW
GW Member Posts: 4,304
I hate to ask a question for the bazillionth time, I have a job where i'm right between a 3 and a 4, I think some of you all go to 20% when the pipes are insulated?

Thanks for the comments
Gary Wilson
Wilson Services, Inc
Northampton, MA
[email protected]

Comments

  • Danny Scully
    Danny Scully Member Posts: 1,329
    The pickup factor can be excessive sometimes @GW. When piping is insulated I feel comfortable rounding down. If it isn’t insulated, you can always measure the pipe length/diameter etc.
    IronmanGW
  • pecmsg
    pecmsg Member Posts: 2,335
    From a cooling standpoint we round down: (Within reason)

    90+ % of the time the equipment is oversized anyway.
    On the few times your at or near design conditions (in your case) a sweater or blanket can be used.
    The envelope can and always is tightened.

    ethicalpaul
  • Steamhead
    Steamhead Member Posts: 14,841
    Is this for a steam or hot-water system?
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Danny Scully
    Danny Scully Member Posts: 1,329
    Well it’s in strictly steam @Steamhead, but i guess we shouldn’t assume.
  • GW
    GW Member Posts: 4,304
    Lol steamer, pick up is .33 in the manufacture sizing charts. But if we’re talking 15 or 20 then that means smaller. Thanks
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • In addition to the above, if it is low mass convectors, then definitely round down. With convectors, it seems if the boiler is sized using conventional methods it tends to bounce off the pressure control during standard heat calls, creating a lot of short cycling. The newer low mass radiators can tend to do that more too, but not nearly like convectors.
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  • GW
    GW Member Posts: 4,304
    Thanks it’s good old USA cast iron rads.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,299
    If you round down and still have some pickup I would say you are ok.
  • Steamhead
    Steamhead Member Posts: 14,841

    Well it’s in strictly steam @Steamhead, but i guess we shouldn’t assume.

    You know what they say "assume" means.............. >:)

    What model series of boiler do you plan to use? It may be possible to use a 4 section and down-fire it, which might result in better efficiency.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • GW
    GW Member Posts: 4,304
    Merry Christmas to all heat people

    I’m at 450 sq ft

    One local vendor doesn’t carry lots of oil steam. I normally go with peerless . One other vendor does have the Smith, so I’ll probably go with the 4 section and be a bit oversized
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Ironman
    Ironman Member Posts: 6,570
    If its oil, you can't beat the MegaSteam.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 10,299
    Both the Peerless and Smith small steamers seem pretty good
  • SuperJ
    SuperJ Member Posts: 605
    If the rads are painted a metallic color or enclosed with some sort of limiting cover, would be safe to downsize accordingly?
    GW
  • Dave0176
    Dave0176 Member Posts: 1,172
    Peerless EC-03 puts you right there at 446 sq ft.
    DL Mechanical LLC Heating, Cooling and Plumbing 732-266-5386
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    GW
  • GW
    GW Member Posts: 4,304
    SuperJ said:

    If the rads are painted a metallic color or enclosed with some sort of limiting cover, would be safe to downsize accordingly?

    good call yet all the rads are out in the open
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • GW
    GW Member Posts: 4,304
    Dave0176 said:

    Peerless EC-03 puts you right there at 446 sq ft.

    hummm I missed that lemme see if the vendor can grab one from one of their branch stores, thanks
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • mikeg2015
    mikeg2015 Member Posts: 1,183
    > @GW said:
    > If the rads are painted a metallic color or enclosed with some sort of limiting cover, would be safe to downsize accordingly?
    >
    > good call yet all the rads are out in the open

    TRVs can work. But pricey.

    Some baffles between sections or attached to the bottom of the radiator would reduce capacity.

    Some black silicone coated canvas cut to shape might work. Can glue with RTV.
  • GW
    GW Member Posts: 4,304
    Thanks I got an SGO-4 on the way
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]