If the hot tap to the bath is running, there is not hot water at the basin

Discussion in 'Plumbers' Talk' started by Grem, May 3, 2021.


Why does water fail to come out of the hot tap on the wash basin when the hot bath tap is running

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  1. Grem

    Grem New Member

    Why does hot water fail to come out of the basin tap if the bath hot tap is running?
  2. pppmacca43

    pppmacca43 Active Member

    Has this been a long term problem or only recent? What system do u have, a combi boiler, or vented/unvented cylinder?
  3. terrymac

    terrymac Screwfix Select

    Because the bath tap outlet is lower than the basin taps outlet ,and you don't have enough pressure to supply both simultaneously !
    pppmacca43 likes this.
  4. Grem

    Grem New Member

    We only moved to the house a couple of months ago and it was shortly afterwards we realised what was happening. Due to the age of everything I think the cylinder is probably vented. The boiler (as shown) is a Warmflow boiler with this weird (?pressure?) tank above. There appears to be good pressure at the bath hot tap ( 11 seconds for 1 litre of water, but not so good at the wash basin (13 seconds) Our shower is also quite low pressure (12 seconds).
    We would like to refit the bathroom and replace the current 22, year old oil boiler, this summer. We are looking at lpg due to modern regs on oil tanks ( previous owners son put the tank on top of a drain!!!) Any suggestions on boiler type eg combi etc and also electric or hot/cold water shower would be greatly appreciated.

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  5. pppmacca43

    pppmacca43 Active Member

    The vessel above is an expansion vessel, completely normal, and fitted in the majority of systems now, but sometimes is within the boiler.
    If u are thinking of upgrading, your best bet is to get a plumber to survey and see what mains pressure and flow rate u got before deciding whether you go down the LPG combi route or a normal boiler with an invented cylinder, or if the incoming main is low pressure a vented cylinder incorporating a pump. Other option I suppose would be a break tank and pump but this is probably less common in domestic settings.
  6. Grem

    Grem New Member

    Thank you

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