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Remodeled House. Now Radiators Are Way Too Large

Alan (California Radiant) Forbes
Alan (California Radiant) Forbes Member Posts: 4,463
in THE MAIN WALL

We installed this boiler and radiator system in 2017 when the owners purchased this house. Nothing had been done to the building since it was built; single glazed windows, no insulation.
I sized the radiators for 130F water temperature as I wanted the boiler to condense and they turned out very large. My supplier says I order larger radiators than anyone else. I suppose that’s a compliment.
Recently remodeled, the radiators are now way oversized and I can drop the heating curve even lower. It’s now set to 1.1 with zero offset and the radiators will only get warm, not hot. Safe for their new children and more savings on their utility bills.

IMG_3401.jpeg IMG_3399.jpeg IMG_3397.jpeg
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
GGrossmattmia2delcrossvPC7060KaosIronman

Comments

  • bjohnhy
    bjohnhy Member Posts: 110

    Nice. Is the reason for the reduced heat lost because of their new insulation, windows, and air tightening? I suppose you do not have a new design water temp yet? But now much lower than 130F?

  • Big Ed_4
    Big Ed_4 Member Posts: 3,224

    Flat curve comfort too..

    There was an error rendering this rich post.

    bjohnhy
  • GGross
    GGross Member Posts: 1,526

    and a sweet little Mesa combo amp in there too, you didn't use that as your table during the project did you?😁

    Alan (California Radiant) ForbesRedbaran
  • hot_rod
    hot_rod Member Posts: 25,171

    what sort if delta do you design for? With a 30 delta you have some cool return temperature

    You were “future-proofing “ before it was in the news!

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    Mad Dog_2
  • tocker
    tocker Member Posts: 34

    Good problem to have. I noted that it appears you selected the 2 sided (runtals?) You may be able to replace with the single sided as a replacement using tge same valves and be just fine. Then just resale these doubles. Singles have a considerably lower output

  • jumper
    jumper Member Posts: 2,460

    So what is the answer? Lower water temperature or slower water circulation? Theoretically either method can go too far.

  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,463

    @tocker That’s not going to happen. The owners spent a lot of money to get the mass to drive efficiency. Changing radiators to smaller ones would mean increasing the heating curve; reduced efficiency.

    The existing heating curve is approaching a radiant floor.

    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
    PC7060mattmia2

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