How water return pipe transferring heat to radiator return pipe

Discussion in 'Plumbers' Talk' started by Rust, Jul 2, 2020.

  1. Rust

    Rust New Member

    We have a new Worcester greenstar life 35kw system boiler running h/w, central heating rads and also UFH via a 4 port manifold. The boiler is on the ground floor with UFH manifold and pressurised tank all in the cellar. The flow pipe from the boiler goes to the cellar where there are 3 two port valves (h/w, rads and UFH). The rads pipe then goes straight to the first floor where it serves 6 rads and then comes down to ground floor where there are 3 rads. The return pipes from UFH and h/w are in the cellar and they meet the rads return pipe on the ground floor before going back to the boiler.

    During the warmer weather I’ve noticed that when the h/w is on it is circling round the system and the h/w in the return is going up the rads return pipe as well as to the boiler, ie in reverse to normal heating circuit. So the rads upstairs get warm through the return valves only.

    This system was all installed at the end of last year as part of an extension and refurbishment. The rads circuit was untouched but everything else was new. What could I do to stop this happening. Do I need another valve on the return or could I fit a non return valve to the radiator return pipe?
     
  2. nigel willson

    nigel willson Screwfix Select

    Get back ppl who installed sounds like piping error to me
     
  3. Mike83

    Mike83 Screwfix Select

    The underfloor heating and radiators should be teed into the return before the hot water return.
    Basically the hot water return comes last before going back to the boiler.
     
    nigel willson likes this.
  4. Rust

    Rust New Member

    The UFH and h/w are in the cellar whilst rad return is on ground floor. We have a tiled floor so no access to those pipes anymore unfortunately
     
  5. nigel willson

    nigel willson Screwfix Select

    Unfortunately just cos you don’t have access does make the problem right. Get the ppl back, it then their problem
     
    masterdiy likes this.
  6. Heat

    Heat Screwfix Select

    Regardless of the correct way to have teed off, the return pipe, it can be possible that the hot water passing through the return will rise (gravitate) if a pipe is teed and piped where it could although heat to rise.
    Anyhow, it is your installers job to correct it
     
    masterdiy likes this.
  7. Crowsfoot

    Crowsfoot Screwfix Select

    Personally Rusty I'd simply turn the radiators off.
    Non return valves always spell T R O U B L E at some stage.
    keep it simple is my advice.
    PS No turnable valves on the rads?
    Then it's been designed as a by-pass (to distribute the excess heat from the boiler).
     

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