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Discuss Poor flow of hot water from new mono mixer tap in new fitted kitchen in the Valves & Taps area at

  1. Homeowner_seek_advise

    Homeowner_seek_advise New Member

    Would be very grateful for any comments about the following:

    Had new kitchen fitted at end of last year - same company supplied and fitted.
    I have a dispute that the tap fitted is not fit for purpose.
    I think the flow from the hot water tap is unacceptably slow.
    It takes ~ 4 1/2 mins to fill a standard kitchen basin to the rim.
    (no problem with flow from cold)
    It takes ~ 1 min using the hot water tap in the bath.
    The new tap fitted is a mono mixer (Alba, Carron Phoenix).
    I’ve asked that the tap and sink be replaced - with what was there before as flow was better (mixer tap but not monobloc).

    It’s a 2nd floor flat and the hot water system is gravity fed and the tank is on the same floor as the kitchen (and bathroom). The cold water for the kitchen comes directly from the mains.

    With regard to the mono mixer tap I’ve since read that high water pressure is not necessarily required but I believe that the water pressure of the hot and cold should be similar, otherwise flow can be disrupted.
    Didn’t know or think anything about taps before all of this ! :)

    The company refuse to replace the tap saying that they ensured it was suitable for low pressure.
    I’ve since gone to Citizens Advice who suggested I seek expert advise (he said can be anonymous) and go back to the company and ask to escalate my complaint and perhaps go via Alternative Dispute Resolution if available.

    I was wondering if anyone had any comments on the acceptability of the hot water flow in the kitchen, or any potential issues with the tap that was chosen - based on water pressures in flat.
    Or should I just accept? Not unusual situation in flats?
    I’m on steep learning curve about water pressure and taps and would be very grateful for any advise :)

  2. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    Show us the new tap
  3. CBW1982

    CBW1982 GSR Top Contributor!!

    Good evening Sylvia,

    I have just looked at the tap on CarronPhoenix website and minimum pressure is 0.2bar, which you may or may not have. What can be the issue is how it is plumbed in. The bath will fill quicker as it will be fed in 22mm pipework from your cylinder, and your kitchen sink will not be. However if it was ok before then I would say something has changed other than the tap. The cold will be noticeably quicker as it is fed from the main and not gravity.

    Are you able to see/photograph the pipework?
  4. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    As above, the manufacturers reccomended a minimum pressure of 0.2 bar. @YorkshireDave@YorkshireDave should be able to explain this better to you, but If your tank is on the same floor as your kitchen I can assume you probably have less than 1m of head from the top of your tap to the base of your tank. This will give you less than 0.1 bar of pressure so you could argue the tap has been incorrectly spec'd. But hypothetically, if you raised your tank a further 2m, to push your pressure over 0.2 bar, you likely still would not have the flow rate in which you desire. There's other factors other than pressure that play a role.
    • Agree Agree x 1
  5. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    You have a very low pressure hot water system - less than 0.1 bar.
    No current ceramic disc based tap is going to give you good flow. You need a tap with conventional valves.
    The problem is probably exacerbated by restrictive (flow) isolation valves In your instance, the only acceptable valves are full bore ones.
    • Like Like x 1
    • Agree Agree x 1
  6. Ben-gee

    Ben-gee Plumber Top Contributor!!

    As above, you need a tap with compression valves (screw down, with washers -“old fashioned”).
    It would also be much better to get one with a dual flow spout.
    Just as an aside, in this situation I would have advised to have a pair of taps rather than a mixer if you could work with this, if not then go with the above.
    • Like Like x 1
  7. Homeowner_seek_advise

    Homeowner_seek_advise New Member

    Very grateful for all the comments - thank you!
    I’ve attached a photo of the new tap and also pipe work underneath the sink and it going back to the original pipework.
    I think the highest point of new tap sits approx 1.25m higher than the base of the hot water tank.

    I gather from all your comments that the problem i have with the hot water flow is perhaps not unexpected and that there are options to improve it. (The flow from the hot water tap in the old kitchen was not very strong but better than what I have now).

    The designer did a site visit. He saw where the water tank was etc. He never mentioned any potential issues.

    Do you think I can go back to the company and say again that the tap fitted is not appropriate (requires minimum pressure 0.2 bar) and that this should have been foreseen?






  8. SimonG

    SimonG Trusted Plumber

    Attack of the kitchen fitter lol.

    Those flexi''s, struggle to get a pipe cleaner through.

    More interested where cold feed tank is rather than hot water cylinder.
  9. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    As above, cold tank which feeds the hot water cylinder is whats more important. You could try work out a resolution with the kitchen fitter, but be realistic as to what results you should expect. Changing the iso valves to full bore, swapping the flexi's to copper and if a high pressure airator is fitted in the tap outlet, switching this to a low pressure outlet should give a noticeable difference.

    If you do manage to get them back, so that your install complies with water regs, ask them to fit a double check valve before the washing machine/dishwasher valve.
    • Agree Agree x 1
  10. YorkshireDave

    YorkshireDave Plumber Top Contributor!!

    Advice above, as always, is good. However, any ceramic disc tap WILL NOT FLOW adequately.
    It needs to be conventionally valved
    • Like Like x 1
    • Agree Agree x 1
  11. Gasmk1

    Gasmk1 GSR

    those shut offs are not full bore either, they should be replaced as they constrict flow
    • Agree Agree x 1
  12. Homeowner_seek_advise

    Homeowner_seek_advise New Member

    Cold water tank sits immediately above the hot water tank (photo attached).

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