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Is internal circulator needed?

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kinghoward
kinghoward Member Posts: 7
in Radiant Heating

Existing boiler set up is a 1/25 hp Grundfos pump on primary loops and the boiler (80k btu, hangs on wall) is on a secondary loop. A T-branch runs a few feet to boiler and back to primary loop. The boiler has a small circulator inside the cabinet. The question is: if I replace this boiler with a boiler that does NOT have a circulator on this secondary loop, should I expect any problems getting heated water back to the primary loop? I'm planning on getting one with more btu per hour, approx 100k btu. Thank you so much!

elsdhs

Comments

  • mattmia2
    mattmia2 Member Posts: 13,505

    each loop needs a circulator for water to flow in it. the boiler loop could have an integral circulator to the boiler or an external circulator

  • mattmia2
    mattmia2 Member Posts: 13,505

    why are you increasing the size of the boiler? you need to make sure the piping is big enough to move that much heat and that whatever you are dumping the heat in to can emit that much heat.

  • kinghoward
    kinghoward Member Posts: 7

    Thank you. Response to your question:When it gets 20 below zero here in winter, the current 80k btu boiler doesn't maintain temperature. 1600 sq ft house , 2 story, built 1905. We have supplemental electric baseboards, too, but the temps usually fall overnight when its that cold, even with boiler running all night. I will double check the items you mentioned and do some thinking. Much appreciated

  • 109A_5
    109A_5 Member Posts: 2,488

    Just for consistency, I believe the Boiler loop is the Primary. The Zones are the Secondary loops.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    mattmia2
  • hot_rod
    hot_rod Member Posts: 25,357

    It could be you need more heat emitters, not a larger boiler?

    It sounds like you have a primary secondary piping, do the boiler would need a circulator

    What brand snd model if boiler and what do you have for heat emitters radiant, baseboard or cast radiators?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    mattmia2
  • mattmia2
    mattmia2 Member Posts: 13,505
    edited July 26
    https://forum.heatinghelp.com/discussion/comment/1860980#Comment_1860980

    or the cold weather end of the reset curve needs to be hotter.

  • pecmsg
    pecmsg Member Posts: 6,291
    https://forum.heatinghelp.com/discussion/comment/1860978#Comment_1860978

    Where is Here?

  • HVACNUT
    HVACNUT Member Posts: 6,871
    edited July 26

    I know you don't need primary/secondary piping on certain Navien boilers feeding a hydro coil within "X" feet of the boiler. But that doesn't help you, does it?

    Different manufactures differ a little here and there from each other. That's why there's manuals for each, and not just one manual that covers all makes and models. Its nice they do that for us. So we know for sure.

  • kinghoward
    kinghoward Member Posts: 7

    Thank you for the comments and corrections. The house is in upper midwest of US. The existing boiler is a WMB -80C. The big gasket on the back leaked badly but we managed to stop leak and get through last winter. Disappointed that this gasket deteriorated and leaked. It has baseboard hydronics and one tall cast iron radiator (it was steam so it only fills partially with water). As a backup, we have electric baseboards here and there in the house. Thanks again, comments and questions welcome.

  • Jamie Hall
    Jamie Hall Member Posts: 26,189

    Major clue here. Baseboard hydronics and one tall radiator which, evidently, either can't be or hasn't been bled adequately.

    I'm not at all sure that a bigger boiler is going to help you. You need to look at those baseboards and measure them up (the actual finned elements, not the overall length) and get the size of the radiator. Then figure out how much heat in BTUh those can put out. That is the maximum size of boiler that will be of any use.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    kinghowardmattmia2
  • kinghoward
    kinghoward Member Posts: 7

    Thank you.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 18,247

    If the old boiler is in otherwise decent shape, why not re gasket it? Or is the metal deteriorated from it leaking?

  • kinghoward
    kinghoward Member Posts: 7

    Thank you.

  • kinghoward
    kinghoward Member Posts: 7

    Good point, EBEBRATT. We were able to scrape around the gasket and seal up with high temp red gasket stuff to get by. We are just looking at options because we have the time. Or if boiler fails, it is at least 5 years old condensing high effeciency so I'm thinking they dont last that long. Thank you

  • mattmia2
    mattmia2 Member Posts: 13,505

    what brand is this boiler? there are a few that have hx issues. most are good for a decade or 2 or more

  • kinghoward
    kinghoward Member Posts: 7

    Mattmia2 : brand is a WMB 80C. Weils McClain. 92.4% AFUE. Direct vent. Discontinued model.

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