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Thermostatic mixer shower...

Discussion in 'Plumbing and Central Heating' started by paul78, 30 Nov 2011.

  1. paul78

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    When fitting a thermostatic shower off a combi system are the hot/cold feeds just branched of the bath hot/cold pipes??

    And if fed off a gravity system can you just tee off the bath pipes again?? (making sure the mixer is suitable 1st that is)

    Just heard contradicting advice today on them so thought id check opinions of you guys

    advice much appreciated.
     
  2. seco services

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    Combi then branch off existing hot/cold.
    Gravity system then i always use dedicated supply from cws and cylinder.
     
  3. shagty

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    This advice was probably relating to the pipework serving the shower valve.

    Stable temperature control on showers with low pressure (gravity) water supplies is dependent on the water source. Shared connections will cause pressure fluctuations and unstable temperature, while dedicated connections can overcome this condition.

    Dedicated connections involve running pipes directly from the CWS cistern and cylinder on such storage systems. Using shared connections on a gravity shower in a home with a few or more occupants can lead to problems.

    Whereas combi systems generally operate at higher water pressures and the effects of shared connections is considerably reduced.

    Hope this clear thing up a bit :)
     
  4. cantaloup63

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    In what circumstances would a pro install a pre-mixer (anti-scald) blender?
     
  5. paul78

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    seco thanks i know what you mean with the dedicated feed to the mixer, what would be the negatives if the mixer wasnt supplied with its own feed and just branched of the hot/cold pipes to the bath or basin...

    thanks
     
  6. seco services

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    pressure/flow fluctuations and unstable temperature.
     
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  7. shagty

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    For non-domestic plumbing applications in healthcare/childcare projects, anti-scald measures are required. For domestic projects where vulnerable people have access to the plumbing system, anti-scald measures would be wise. Plumbing systems with sold fuel heat sources would also warrant such measures.

    Most quality thermostatic mixer valves feature anti-scald devices.
     
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  8. cantaloup63

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    Do most modern (new)builds have to be part M compliant and thus these valves fitted to (or specified) mixer taps as standard? Indeed, in an example of either a bidet or WC doucher shower would it be necessary?
     
  9. shagty

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    I think construction standards associated with plumbing are confined to part G of the regs.

    The regulations for England, Wales and Scotland include the requirement that baths are fitted with anti-scald devices, whereas all other fittings appear to be excluded. Scalding risks are higher with baths when compared to basins or sinks for example.

    This is somewhat analogous to breaker disconnection times for fixed and hand held electrical appliances.
     
  10. shagty

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