1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Shower from combi not really hot enough

Discussion in 'Plumbing and Central Heating' started by WabbitPoo, 19 Jan 2021.

  1. WabbitPoo

    WabbitPoo

    Joined:
    26 Feb 2005
    Messages:
    2,759
    Thanks Received:
    141
    Location:
    Gwynedd
    Country:
    United Kingdom
    We have two of these showers fitted in the house:

    SIREN SL EXPOSED MIXER SHOWER

    One has been there for 3 years and the other one just installed (by me)

    The original one has been great, except that I find it necessary to turn the heat control knob more and more to the hot end to get a good hot shower. The newer one is already like that, and in fact a little worse as you don't really get a HOT shower at all...just hot-ish, if you know what I mean.

    The basins in the two bathrooms, which share the same feeds as the showers in either case, are plenty hot enough - in fact, you'd burn yourself if you just used hot water in the basins.

    Might there be an issue with the thermostats in the two showers themselves? If so, are they adjustable in any way?
     
  2. Sponsored Links
  3. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    73,410
    Thanks Received:
    4,226
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    no

    it's winter.

    combis do that.

    let's suppose your combi has the power to raise the temperature of 11 litres of water delivered by the boiler to the hot water taps with a temp rise of 35 degree C. So if the temperature of the incoming water main to your house is 10 degree C then the boiler will raise that temperature by 35C to 45C

    let's suppose you shower delivers 11LPM.

    Let's suppose that in summer the incoming water supply from the mains was at 15C.
    The water at your shower would be (15+35=) 50C which is fairly hot.

    lets suppose it is now winter and the incoming water supply from the mains is at 5C.
    The water at your shower would be (5+35=) 40C which is not very hot.

    You can turn down the mixer tap to deliver less water, and it will get a bit hotter.

    Run your shower into a bucket, time it to full, calculate how many litres per minute of hot water it is delivering.
     
  4. WabbitPoo

    WabbitPoo

    Joined:
    26 Feb 2005
    Messages:
    2,759
    Thanks Received:
    141
    Location:
    Gwynedd
    Country:
    United Kingdom
    Thanks. I get what you're saying but I fitted the 2nd shower in the early summer (only just got round to using/fixing it!) so not sure the issue is one at the boiler. Plus, the basins are very hot..
     
    Last edited: 19 Jan 2021
  5. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    73,410
    Thanks Received:
    4,226
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    after you've bucket-tested the shower, do the same with the basin tap.

    I bet you 50p you will find it is delivering less water, and the temperature is therefore higher.

    use a thermometer if you have one.
     
  6. Sponsored Links
  7. WabbitPoo

    WabbitPoo

    Joined:
    26 Feb 2005
    Messages:
    2,759
    Thanks Received:
    141
    Location:
    Gwynedd
    Country:
    United Kingdom
    its all fed in 15mm...why would the basin be delivering less? Anyway, winter/summer doesn't seem to apply, given it was the same in the newer shower back in the summer.....

    Appreciate the help.
     
  8. JimCrow

    JimCrow

    Joined:
    31 Jan 2011
    Messages:
    649
    Thanks Received:
    226
    Location:
    St. Kilda
    Country:
    United Kingdom
    Siren valve commissioning.PNG
     
    • Thanks Thanks x 2
    • Like Like x 1
  9. WabbitPoo

    WabbitPoo

    Joined:
    26 Feb 2005
    Messages:
    2,759
    Thanks Received:
    141
    Location:
    Gwynedd
    Country:
    United Kingdom
    ooh thanks....I'll take a look tomorrow in the light.
     
  10. WabbitPoo

    WabbitPoo

    Joined:
    26 Feb 2005
    Messages:
    2,759
    Thanks Received:
    141
    Location:
    Gwynedd
    Country:
    United Kingdom
    Thanks chaps - sorted.
     
    • Like Like x 1
  11. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Loading...

Share This Page