Thermostatic shower, mains cold, gravity hot

Discussion in 'Plumbers' Talk' started by ChrisHigs, Sep 9, 2018.

  1. ChrisHigs

    ChrisHigs New Member

    I've got an old Triton thermostatic shower pumped under the bath which has started leaking recently so I've turned off the supplies to it and want to replace it with a new shower.

    I've had a look under the bath and the hot and cold are both pumped up to the shower, even though the cold is mains fed (comes straight off the pipe from the bath taps which is definitely off the mains).

    From what I've read though this is not the correct way to do it and the cold should also be from the cold tank on the attic.

    Is there some way I can use the current pipes with a new thermostatic shower? Maybe just put a pump on the hot side? Would I need a non return valve and pressure equalising valve to equalise the pressures?

    Would it be better to run a cold feed from the attic?

    Thanks
     
  2. Heat

    Heat Well-Known Member

    Better to run a cold feed from the attic. Has to be solely for the pump cold supply.
    Just make sure the basin and toilet are separate and not going to be linked to the pump.
    Best with mains to basin and also to toilet cistern if it has suitable fill valve
     
    The Teach likes this.
  3. ChrisHigs

    ChrisHigs New Member

    I was expecting that to be the reply but hoping there would be an easier way than putting a new cold supply in.

    Yeah the mains cold feeds the toilet, sink and bath taps, only thing that the cold water tank is being used for is the hot water tank.

    I'm wondering if it might be easier to put an electric shower in but never really found them powerful enough. Wasn't expecting this to be so complicated, thought it would just be swap over old bits for new.
     
  4. Pollowick

    Pollowick Well-Known Member

    You can run the shower with mains cold and pumped hot. You will need to know your approximate static mains pressure and flow rate then match teh pump to the pressure (approx). NRVs may be needed but may not.

    Have a look at the Stuart Turner pumps - their Monsoon range are excellent, work out what you need, probably a Universal 2 or 3 bar single and call their Pump Assist line to confirm your needs. The Monsoon are not the cheapest but have 5 year warranty and are very quiet, however there is also the cheaper Showermate but only a 2.6 bar single
     
  5. NoOhmToGoTo

    NoOhmToGoTo Active Member

    Heat is sort of right in that if you were planning this then that is how you should do it.
    However, you are where you are, so connect up your cold mains to the shower and then use a negative head single impellor pump to boost your hot water. There was a similar post a week or so ago.
     
  6. ChrisHigs

    ChrisHigs New Member

    Wow, yeah those Stuart Turner pumps are not cheap compared to some others.
     
  7. ChrisHigs

    ChrisHigs New Member

    I'd prefer to not have to run new pipes if I can get away with it. Maybe if I was redoing the bathroom I'd do that. So if that's an option not to i think I'll go for that.

    Those Stuart Turner pumps aren't cheap. So if I went for a 3 bar single universal pump would I need anything else? Equalising valve between the two?

    What's the benefit of the negative head pump over positive head if I've got positive head? And would a universal be ok?

    Thanks
     
  8. The Teach

    The Teach Well-Known Member

    I imagine the new twin impeller pump will ask for both hot & cold supplies to be fed from a loft tank.Maybe get a plumber in to run a new supply and fit the pump,some new pumps are quiet sensitive & fussy items.

    They dont make them like the use to :(

    Having mains cold water connected to a twin impeller pump can make them leak water,some leak sooner than others :(
     
  9. Heat

    Heat Well-Known Member

    Definitely yes. I meant cold gravity water from cold water tank.
    All the pumps I have seen leaking were incorrectly piped. Except one that I had previously installed (properly), but it had lasted 20 years of regular use. :)
    The Stuart and Turner Monsoon pumps are my preferred type
     
  10. Heat

    Heat Well-Known Member

    You only require a negative head pump if you don’t have any, or not enough head of water for a positive head pump to start.
    Or where the pipes have restrictive flows - like low head overhead runs before dropping.
    Negative head pumps work if an outlet is opened, whereas positive head pumps only work with flow switches
     
  11. Pollowick

    Pollowick Well-Known Member

    They may not be cheap, although there are some wholesalers who have good prices, but you will be getting one of the best pumps there is, with a good warranty and support if required.
     
  12. Peterdevon

    Peterdevon Active Member

    You could fit a venturi shower, I have in the past and they worked better than electric!
     
  13. The Teach

    The Teach Well-Known Member

    Fitted many venturi shower mixer valves,a great problem saver. Dont think they are made anymore :( Some stock may still be around,cost around £350 per mixer valve !
     
    Last edited: Sep 13, 2018
  14. ChrisHigs

    ChrisHigs New Member

    Thanks for the replies. Still unsure what to do.

    I've read some mixed reviews about the venturi type showers, and that moving the shower head around can affect the heat of the water. Sounds like a good idea if it works well enough though.

    Tempted just to try a single impeller pump and see what happens, even though I know it's not the correct way to do things.
     
  15. Pollowick

    Pollowick Well-Known Member


    As I said before, nothing wrong with, just not the perfect way. Call Stuart Turner - pump specialists and ask their opinion, which may well be "nothing wrong with that way"...
     
  16. ChrisHigs

    ChrisHigs New Member

    Quick phone call to their pump assist line and they said it should be fine.
     
  17. ChrisHigs

    ChrisHigs New Member

    So quick question. If I use one of their pumps just on the hot should I fit any non-return valves, pressure equalising valves, etc. or just the pump?
     
  18. Pollowick

    Pollowick Well-Known Member


    NRVs will depend on your shower. Some have them integral, others do not. You should not need an equaliser valve if you match - but ask Stuart Turner - they have a team willing to advise and assist who are quite used to the simple idiot question right through to the highly complex ones. The call is free and if they are busy, they will take your number and call back.
     
  19. NoOhmToGoTo

    NoOhmToGoTo Active Member

    Tell me Chris, why did you post on this forum?
    I gave you chapter and verse, direct from a pump manufacturer 10 days ago, and yet you haven't accepted it until you rang Stuart Turner.
    So, why didn't you ring them from the get go and save everyone a load of time?
    Just askin' like.
     
  20. ChrisHigs

    ChrisHigs New Member

    I didn't realise there was a number I could call for advice before posting on here, and the first reply (and another later on) did say I should install a new pipe from the cold water supply in the attic. Yes I probably should have rung them sooner than I did, but I wanted to make sure that it was a viable option before purchasing anything. Thanks everyone for the advice, pump ordered, just need to order a shower now, so hopefully will be up and running again soon.
     

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