Shower Pressure/flow rate low on new bathroom

Discussion in 'Plumbers' Talk' started by AlShaw, Mar 20, 2017.

  1. AlShaw

    AlShaw New Member

    Hi,

    My plumber has finished my bathroom and installed a new unvented boiler system with a megaflo cylinder.

    Pressure to the property is good and high on taps.

    But the shower is very so-so and about what it was with the old combi boiler/bathroom. It has less pressure/flow rate than it could in my view. The plumber says that is just how it is and there is a 'restrictor valve' in these devices. He seems resigned to there being nothing that can be done, stating "that's how they all are, if you replace the valve with another it will be the same". But this can't be true, obviously some people, houses, hotels, etc have very high pressure/flow rate.

    Is there anything that can be done?
     
  2. Yes - and it starts with a new plumber...

    OK, he may be right to some extent - there could well be restrictors inside the shower valve as some models have to cope with all sorts of plumbing types from very low pressure (vented storage tanks) right up to what you have.

    A combi should give a good shower, but an unvented setup like yours should be awesome - real power-shower type.

    What make and model is your shower valve?
     
  3. Crowsfoot

    Crowsfoot Screwfix Select

    What was the pressure on the shower like before the unvented install Al ?

    Might there be a blockage in the pipework?

    Disconnect the shower head from the shower and give it a try; this would be a good starting point.
     
  4. AlShaw

    AlShaw New Member

    Thanks, no blockage, will try head.

    This is the model

    https://www.victorianplumbing.co.uk...gid-riser-kit-diverter-12-shower-rose-handset

    Plumber says the restrictor is built in and even if it could be removed it'd be a big task taking it apart again.

    Pressure / flow rate was identical with old boiler and old shower.

    Plumber mentioned there are 15mm pipes everywhere and ripping them all up for 22mm would help but a huge task.
     
  5. I can't see anything about flow restrictors in the instructions - that shower seems able to cope with huge pressure ranges, and vented and unvented systems right up to 5 bar (which is a LOT).

    Also, since your internal water supply is fed by mains pressure, 15mm pipes are fine, and there would likely be no noticeable difference in going up to 22mm (that's chust for gravity - vented - systems).

    So, I'm not convinced your plumber is fully on the case here.

    When you had a combi, the flow rate was governed by the DHW capability of the boiler. Now that you have a hot water store which is pressurised up to around 3bar, there should be virtually no governing at all - your taps and shower should BLAST!

    A couple of things to try so's we know chust how 'bad' this is - can you measure the max flow rate coming out your shower head? Point it in to a bucket and run it FULL for exactly 10 seconds. Measure the quant of water and 'times' it x 6 and you have 'litres per minute'.

    Compare this with your cold kitchen tap. Actually, can you compare it with your hot tap too?

    MAX flow in all cases.
     
    Mike83 likes this.
  6. AlShaw

    AlShaw New Member

    Thanks Devil's advocate this is all really helpful. I'm not at home now to check everything but if you look on page 2 of the manual it mentions 'strainers' which is another word I think for these restrictors.

    I'd also need to test this like you say but my impression is water comes out for the bath taps at a higher pressure/flow rate.

    The kitchen taps is relatively weak but fine for a kitchen tap and the plumber showed me a restrictor in its head.
     
  7. This is what I looked at: https://images.victorianplumbing.co.uk/images/pdf/dual_concealed_exposedVICEXSV12.pdf

    Where are these strainers?

    In any case, strainers/filters are NOT the same as restrictors, and shouldn't restrict to any noticeable degree.

    It is common to have actual flow restrictors in shower valves so's they can cope with high and low pressure water systems, so I'm a bit surprised yours doesn't have this.
     
  8. G&W Plumbing & Heating

    G&W Plumbing & Heating Active Member

    Your late tonight dev

    It's basic stuff really and what dev is rightfully saying is your plumber is not good.

    Real good plumbers would of provided system design or mech spec we call it,

    The problem is when doughnuts have been in, its an open book to what they could of done

    Why were you advised Unvented system initially?

    What area are you? I'm happy to sort for you if needed?

    I've got a saying...if you think a professional is expensive.. wait till you hire an amateur!!!

    My money's on unbalanced supplies
     

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