Low Water Pressure

Discussion in 'Plumbing and Central Heating' started by needhelp, 6 Feb 2005.

This topic originated from the How to page called Fitting new taps.

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  1. needhelp

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    Hi.

    Hope someone may be able to help. :confused:
    We have changed our kitchen sink and fitted a new mixer tap - and now have little or no hot water pressure.

    The hot water pressure has always been very poor, and previously we have a standard one hole mixer tap. I have now fitted a one hole mixer tap in the kitchen, with a pull out shower head. However, the hot water now trickles out. All other taps in the property are fine, and the hot and cold water pressure in the bathroom remains ok.

    We fitted as a temporary measure a tap directly onto the hot water tap under the sink (half inch pipe) and the water pressure is good. Is it because I am now passing the hot water from my tank, through the smaller pipe into the mixer tap, and then around the flexy cable to the pull out shower head???

    If that is the case, is there anyway I can boost the pressure around the tap, or will I have to sacrifice, and put in another tap?

    Thanks
    Marc :cry:
     
  2. Bahco

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    Are your supplies balanced or is the cold supplied from the main and the hot from a cylinder. If they are unbalanced you could fit an isolating valve to your cold and turn it down a bit to equalise the pressure.
    What is probably happening is that the cold is overpowering the hot. :(
     
  3. felix

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    Oops, oops and thrice oops. You DO NOT fit one hole mixer taps to kitchen sinks. These only work properly on balanced supplies which means that the cold has to come from the tank that feeds the hot water system. Unfortunately, a kitchen cold supply should always be mains water - because you have to drink it!. A proper kitchen mixer has two distinct exit holes.

    Have you checked your cold tank recently. You might find water gushing from the vent when you turn on the kitchen taps. Furthermore, if the mains pressure fails your tank water can get into the mains pipework. Water boards don't like this at all.
     
  4. needhelp

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    Sorry, maybe I didn't make it too clear.
    The tap I have, is a proper kitchen mixer, with a pull out spray head - as in the picture attached:

    [​IMG]

    It therefore has two exits, and the cold is fed from the mains supply - and the hot from our tank (which sits 1ft above ground level).

    I've been told that a pump is not avalaible to improve pressure, however all taps are sold either for low or high pressure water supplys. Is that true, and if so could it be that the tap I have is just unsuitable for a low pressure water supply.

    I bought the tap in Wickes - and if needbe, I'll replace it for a more simple mixer tap, with a greater pipe diameter (15mm), rather than the flexi cable, which is approx 10mm and two foot in length.

    As suggested by BAHCO, how much more pressure can be acheived by fitting an isolator valve, and turning down the mains cold pressure slightly?
     
  5. Dave Mc

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    Not to make anyone sound stupid! But have you had a look in side the tap to see if there is any crap in it! Or if the valve is moving.
     
  6. felix

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    Since this is a proper two hole mixer, stopping down your cold supply won't help the hot to flow at all, though you will get a trickle of hotter water. The height of your hot tank is irrelevant. The height of your cold tank is what matters. If it's two low you won't get a decent flow out of what is, in effect, a shower head. In fact it's worse than a shower because you must have two concentric pipes in that hose.

    Obviously you should check for blockages but if you have none you can either:

    1) Raise the cold tank.
    2) Fit a pump in the hot supply to your sink.
    3) Take it back and get a regular two hole kitchen mixer tap.
     
  7. needhelp

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    I've checked the tap, and there are no blockages - and the valve appears to be fine.

    Raising the tank is not possible, as I am in a flat - so that's unfortunately not an option.

    However, a pump would be my preferred choice. I've been told elsewhere though, that it's not possible to fit a pump to the hot water supply as it could lead to problems by draining the tank too quickly.

    If a pump is possible, are these the same as a shower pump???
     
  8. Bahco

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    Flats have very poor hot pressure due to position of cold water cistern directly above cylinder which equates to virtually nothing. :(
    Suggest you forget the mixer and do as Felix advised and fit separate taps.
    You could fit a combi if your incoming pressure is up to it and then your mixer will work.
    Expensive option tho........ :LOL:
     
  9. ed147

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    _________________________________
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    Please note forum rule 20 also general information item K
     
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