Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.
If our community has helped you, please consider making a contribution to support this website. Thanks!

Burnham replacement boiler EDR/Pick Up Question

Options
Local1Plumber
Local1Plumber Member Posts: 11
in Strictly Steam

Hey all, this past winter my residential boiler has finally had it. A crack in one of the sections has me heating the atmosphere lol. That said, contrary to what my knees want I will be replacing it this summer and am trying to appropriately size up my replacement. I own "The Lost Art of Steam Heat" for a while now and have been going over all the calculations. Essentially I have about 353 EDR (radiators/blind riser) no pick up factor added in. If I add a 1.33 pick up its roughly 470 EDR. If I multiply 470 X 240 (btu) I will need around 113,000 btu boiler. In regards to a Burnham I'm looking at a "STMX150". Am I missing anything? Again this is for my home so I'm not trying to get "free" advice for help pricing a job. An extra set of eyes is appreciated. Thanks for stopping in.

STMX150NRHPA.pdf

Comments

  • ChrisJ
    ChrisJ Member Posts: 17,481

    That will work but if it was mine id go with the STMX125.

    But personally id recommend a WM EG40 or a Peerless.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • Steamhead
    Steamhead Member Posts: 18,622

    @Local1Plumber , the boiler's square feet rating has the pickup factor built in. If you're going to use a SteamMax the 150 is the right choice. But make sure your steam pipes are insulated and your main vents are properly sized.

    Is this a one-pipe system?

    All Steamed Up, Inc.

    Baltimore, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting

  • Jamie Hall
    Jamie Hall Member Posts: 27,508

    You could just compare your EDR to the EDR rating of the boiler — no conversions needed, the pick up factor is already worked into the boiler rating…

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • mattmia2
    mattmia2 Member Posts: 17,194

    is it 1 pipe or 2 pipe? you can undersize a fair bit with 2 pipe without ill effect. even with 1 pipe slightly under is better than a lot over. unless you have a whole lot of main and riser piping the actual pickup of the system is probably more like 10%.

    KC_Jones
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,764

    353 EDR (output without a pickup factor) x 240 BTU/EDR = 84,720 BTU's.

    Why couldn't he go with a Burnham STMX100 which has an output of 82,000 BTU'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
  • mattmia2
    mattmia2 Member Posts: 17,194
    https://forum.heatinghelp.com/discussion/comment/1897215#Comment_1897215

    the pickup factor covers things like losses from the piping and an output greater than the steady state to heat the system at the start of a cycle. you do need some pickup factor, just usually far less than 30%. the 100 is probably too small unless it is 2 pipe but the 125 is probably perfect.

    Alan (California Radiant) Forbes
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,380

    @Local1Plumber

    You nailed it

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,764

    So, what would be the best choice? Burnham, WM or Peerless? Let’s say his installer would be happy with any of them and there are local suppliers for all brands.

    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

Categories