UFH from Vaillant Ecotec Plus 831

Discussion in 'Plumbing and Central Heating' started by davenuk, 18 Nov 2021.

  1. davenuk

    davenuk

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  3. ScottishGasMan

    ScottishGasMan

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    No it doesn't. You could get someone to fit a VR40 (2in7) relay module that would give you the option of running a CH pump from a relay in the boiler. But any work on the appliance is something that should be done by a gas safe engineer.
     
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  4. davenuk

    davenuk

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    thanks for that, i didn't know they did a module that small, had seen the bigger wiring centres but that was overkill. the other option is to switch the pump from the hive signal with a relay.

    although it seems the boiler is quite happy to drive the water around the UFH without the assistance of the pump (small room, 90m of 15mm pipe).

    thanks again
     
  5. Agile

    Agile

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    Having a separate pump for UFH is probably more associated with a temperature reducing valve and an expectation of UFH tubing smaller than 15mm.
     
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  6. davenuk

    davenuk

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    that's interesting, the ID of the pipe looks around 10mm.

    it's a wunder single room kit and has a pumpset with a mixer valve.
    https://cdn.wundatrade.co.uk/wp-con...nda-single-double-loop-pumpset-13-08-2019.pdf

    i guess it's just the proximity to the boiler which is allowing it to flow, they are next to each other.
     
  7. Agile

    Agile

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    But you said yourself on Friday at 0923 that it was 90m of 15mm!

    Must be very thick pipe!
     
  8. davenuk

    davenuk

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    yes, that was very lazy of me.

    OD is about 16mm I think, but internally its around 10, the batteries in the calipers have expired so I can't say for sure.

    from the datasheet -

    Coil Size 50m, 80m, 100m, 120m, 250m, 500m
    pa_single-bulk 1118, 1796, 1797, 1795, 1787, 1785, 1793, 1791, 1789
    Maximum Pipe Loop Length 100mtrs per loop
    Outside Diameter [mm] 16
    Number of construction layers 5
    Minimum radius of manual bending [mm] 5 x D
    Minimum radius of spring bending 4 x D
    Size 16mm
    Thermal Conductivity [W/Mk] 0.45
    Weight per Kg/m 0.095
    Water capacity of pipe [l/m] 0.113
    Thickness of wall [mm] 2.0
    Pipe Dimensions [mm] 16 x 2.0
    Maximum operating temperature [°C] short term 95
    Absolute Roughness [mm] 0.007
    - Class Application 5 10
    - Class Application 4 10
    - Class Application 2 10
    Coefficient of thermal expansion [mm/Mk] 0.032
    Colour White
    Material Aluminium & Polyethylene
    Inner Diameter [mm] 12
    Guaranteed for LIFETIME
    Design Pressure [bar] - Class Application 1 10


    bon appetite!
     
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  10. Agile

    Agile

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    Right those specs show the diameter as 16mm and the wall thickness as 2mm.

    So that will mean the internal diameter will therefore be 12mm!

    I once went ( under the boiler warranty ) to an installation which had about 40m of 10mm copper pipe which was run in a cut out 12mm ply wood .

    There was no temperature reduction and the full boiler pump output pressure was applied to the tube.

    Unfortunately all the heat had been dissipated after about 3m of the tube!
     
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  11. davenuk

    davenuk

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    :) DIY underfloor heating, nice.

    the floor is connected and the pump wired up manually "for now".

    it works really well, i'm easing the heat in by no more than 5deg increase per day, even at 30 deg C, the floor is warm.

    there are noticeable cold spots in places where there is no pipe, so it's not spreading all that great, but overall i'm very happy with it.

    it's like a wall of heat when you walk into the kitchen.
     
  12. Mr Chibs

    Mr Chibs

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    Once winter comes and the floor is working a bit more (regularly) those cold spots will be less noticeable.

    What screed have you got Liquid/conventional?
     
  13. davenuk

    davenuk

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    it's wundertherm panels over an old tiled floor with instarmac proflex s2 and BAL Salt-Bae's-golden-****ing-tile-adhesive-by-the-price-of-it when we ran out of the proflex on top of that as tile adhesive.
     
  14. Mr Chibs

    Mr Chibs

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    hahaha
     
  15. Agile

    Agile

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    It is fairly normal when fitting UFH on ground floors to have 50mm to 100mm of insulation under the UHF tube!

    So all the heat goes upwards and none is wasted heating the ground!
     
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