Mixer Bar Shower Only Lukewarm

25 Aug 2016
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United Kingdom

Our mixer bar shower has started to only get lukewarm, having googled the issue I was just expecting to find a broken thermostatic cartridge valve in the mixer bar. I've removed the temperature adjustment knob revealing the below,


once I unscrewed it I had this


when screwing the knob in and out the hex part of the above moves in and out.


that's inside the mixer bar.

From what I can see with the valve set all the way to cold the hex part is extended fully and actuates on the silver pin inside the mixer bar, I'm guessing this releases a valve that allows only the cold water to flow. As I then adjust the valve to hot the hex part releases the valve allowing hot water to flow until it blocks off the cold water giving only hot water.

Is my above summising of the workings correct and if so I'm guessing my issue is the valve in the mixer bar isn't releasing properly to stop the flow of cold water and as such I'm getting a constant mix of hot and cold water at a lukewarm temperature? If so how do I repair it or am I just best off buying another mixer bar to fit and this time make sure it contains a serviceable cartridge?

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having googled the issue I was just expecting to find a broken thermostatic cartridge valve
if it was not broken before,it certainly is now (n) Testing or calibrating could have been done before dismantling.

The remainder of the thermostatic cartridge is removable form the mixer,then any limescale or dirt in the mixer needs to be removed so the new cartridge fits easily.

Thermostatic cartridges (decent items) cost £60 + Maybe a new bar mixer valve is the best option and the easiest option if the existing bar is 150mm c/c again a decent brand is recommended not the £19.99 internet offerings :idea:

Hot&Cold is right. I never repair bar mixers as the replacement parts are usually no cheaper than a new shower and the switchover is a 10 minute job. I haven't come across a bar mixer that doesn't have 150mm pipe centres.

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