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

Under w/basin Thermostatic mixer valves

Discussion in 'Plumbing and Central Heating' started by Harry Bloomfield, 27 May 2020.

  1. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    7,587
    Thanks Received:
    1,086
    Country:
    United Kingdom
    The downstairs toilet wash basin originally had a H & C taps, but our H is very H, so I removed the cold tap completely and fitted a mixer in the pipework below the basin, so that only safe warm water was available at the basin. That made it safe for the kids and me when I went in, to wash my hands after working outside.

    Yesterday the flow when the tap was turned on, was but a trickle. Investigating it today, the hot input port was choked up with gunge, cleaned out flow was back to normal, but the mixer allowed full temperature hot through. I'm assuming the cartridge has failed.

    Unit is chromed, with a lockable blue plastic temperature adjuster, marked min, 1 to 5 max. Is it usually possible/ worthwhile to just source a replacement cartridge please?
     
  2. Sponsored Links
  3. oldbuffer

    oldbuffer

    Joined:
    6 May 2010
    Messages:
    1,400
    Thanks Received:
    524
    Location:
    London
    Country:
    United Kingdom
    1. You can get them, but you will need to know the make and model of your TMV. They are not all the same.
    2. You may find there is little difference between the prices of new valves and replacement cartridges.
    3. They usually have filters and non-return valves on both hot and cold. Worth checking both.
    4. They have to be adjusted when fitted (and at their "annual service"). Is it possible you have disturbed the adjustment which now needs to be remade.
     
  4. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    7,587
    Thanks Received:
    1,086
    Country:
    United Kingdom
    No, I only disturbed the hot input port and removed something grey and soggy from it with a finger tip. I assumed the default with a failed wax cartridge is for it to close the cold port completely? Hence the too hot from the tap.
     
  5. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    7,587
    Thanks Received:
    1,086
    Country:
    United Kingdom
    I have now pulled the mixer apart and the cartridge looks very like this one -
    https://www.showerdoc.com/grohe-avensys-wax-thermostat-element-00798000

    But that is a really silly price, more than three times what I paid for the entire valve originally. I tried putting the cartridge in a dish of freshly boiled water, expecting its length to change, but no change I could detect. Where can I get one of these at a sensible cost please?
     
  6. Sponsored Links
  7. Madrab

    Madrab

    Joined:
    4 Oct 2012
    Messages:
    8,036
    Thanks Received:
    2,274
    Location:
    East Renfrewshire
    Country:
    United Kingdom
    Yup, sealed wax sensor, if it won't move in hot water then it's compromised and needs replaced.

    If it's not exactly the one that it replaces chances are it won't work properly, these have very fine tolerances and calibration, only way they can specify its TMV2/3 status. I'd just replace the valve, they're not massively expensive.
     
  8. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    7,587
    Thanks Received:
    1,086
    Country:
    United Kingdom
    I have only been able to find prices between £24 and £55, just for the replacement part and £130 to £250 for the complete valve - have you found a cheaper source?

    The whole unit only cost me £9 new when I bought it.
     
    Last edited: 28 May 2020
  9. Harry Bloomfield

    Harry Bloomfield

    Joined:
    30 Dec 2018
    Messages:
    7,587
    Thanks Received:
    1,086
    Country:
    United Kingdom
    Anyone able to identify for certain, the manufacturers name from the photo above please? It looks as if it might possibly be a stylised W cast into the side of the case, or maybe an I V.
     
  10. flameport

    flameport

    Joined:
    10 Mar 2007
    Messages:
    9,817
    Thanks Received:
    1,962
    Location:
    Poole, Dorset
    Country:
    United Kingdom
    Forget about the old one, it's scrap.

    A random selection:
    £26: https://www.bes.co.uk/thermostatic-mixing-valve-tmv-2-3-15mm-12162/
    £23: https://www.plumbingforless.co.uk/?i=126748
    £19: https://www.tradingdepot.co.uk/speedfit-15mm-easifit-2-in-1-thermostatic-mixing-valve-heat112010
    £32: https://gasproducts.co.uk/15mm-pegler-prestex-peg402-thermostatic-mixing-valve-tmv.html
    Loads of others available everywhere.
     
  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