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Discuss Water Pressure for Kitchen Taps in the Valves & Taps area at


    MCGRAW New Member

    We bought a kitchen tap (Grohe Ambi Contemporary 2 handle sink mixer) some time ago, stupidly without checking water pressure. Return deadline has well passed.

    The instructions say minimum water pressure of 0.4 Bar is required and that operation with unpressured storage heaters is not possible.

    Measuring down from the bottom of the cold water tank in the loft to the top of the new tap suggests we have 0.38 Bar. We also have a hot water cylinder and the boiler is an Ideal Classic.

    Before we get a plumber in, is there any chance of this working or is it a case of cutting our losses and getting another tap?

  2. joni os

    joni os Plumber

    It will work but flow will be less than if pressure exceeded 0.4 bar. the pressure you have measured is the static head, pressure at tap under flow conditions will diminish due to pipe/tap friction losses. These friction losses increase with flow but will not exceed the static head, resulting in equilibrium at given flow.
    Raising height of cold water tank will improve flow.
    Last edited: Oct 19, 2016
  3. Darren Jackson

    Darren Jackson Plumber GSR

    Fitting a pump will increase the pressure but then you may need to install larger volume headers and the cost of a pump and any upgraded header tanks is far more expensive than just cutting your losses and getting another tap?
  4. steadyon

    steadyon Active Member

    If this is installed in the kitchen, then it is highly likely that the cold supply will be direct from the mains and therefore at mains pressure, so you should have no issues with the cold.

    The hot will, assuming your measurements are correct, be virtually at the minimum pressure required, so not likely to give severe problems.

    The tap is not a thermostatic one, so there is no mixing of hot and cold (except at the end of the spout) and should be no issue with mains pressure cold "overcoming" tank pressure hot.

    Its a fairly standard fitting, and I think you'd be well advised to fit it, and take the slight risk that it would have to be replaced.
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