System design query?

Discussion in 'Plumbers' Talk' started by Txm0984, Feb 21, 2021.

  1. Txm0984

    Txm0984 Member

    Recently purchased a house that had been empty for a while with decayed heating system.

    I have the below system setup installed at present.

    The issue is there is no blending valve so I can’t have the boiler at more than 65 degrees.

    I want to separate the cylinder and rad feeds so I can run the boiler at 80 degrees for the rads and cylinder and get approx 55 degree water to the 3 UFH manifolds.

    I can see some potential issues just simply adding it to the primary flow rail etc.

    I have blank ports on the low loss header so I’m sure there is a decent solution. Maybe plumb the rads and cylinder to the boiler and then use the pump after the blending valve just for the UFH manifolds?

    many help appreciated.

    Attached Files:

  2. Txm0984

    Txm0984 Member

    FYI UFH is suspended timber hence 55 degrees not 35 etc
  3. Jimbo

    Jimbo Screwfix Select

    80 degrees flow will cost you more to run as there will be less/no condensing. Making the radiators bigger (or improving insulation) would be a better option, likewise the tank could be replaced with a quick recovery unit.
  4. Txm0984

    Txm0984 Member

    Hi, the rads do well as I over sized them. I wanted a hotter circuit mostly to help the tank get all above 60 degrees
  5. sam spade

    sam spade Active Member

    You don't need the tank over 55-60. You can easily achieve this with the boiler water at 70.

    If the rads have been oversized you should have no problem achieving a 50C return temperature, which will help the boiler to condense more.

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