Under w/basin Thermostatic mixer valves

[Harry Bloomfield]

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?

 

[oldbuffer]

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.

 

[Harry Bloomfield]

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.

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.

 

[Harry Bloomfield]

IMG_0162

• Harry Bloomfield
• 28 May 2020

w/basin Mixer Valve

IMG_0162

• Harry Bloomfield
• 28 May 2020

w/basin Mixer Valve

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?

 

[Madrab]

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.

 

[Harry Bloomfield]

I'd just replace the valve, they're not massively expensive.

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.

 

[Harry Bloomfield]

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.

 

[flameport]

manufacturers name from the photo above please?

Forget about the old one, it's scrap.

£130 to £250 for the complete valve

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.