I've un-fettled the temperature limiting blending valve from the bathroom at Feanor Outposts in Edinburgh.
This device limits the hot water temperature at the tap to luke-warm.
Now I understand why these might be appropriare in certain scenarios, this is not one of them.
The main downside is that although the temperature is *just* ok when you fill the bath, it's not possible to top it up when it cools.
That requires a smallish volume of properly hot water.
Trying to top up with water thats only a few degrees warmer than the bath means you pretty much need a full tub volume!
The pipework was JG speedfit, mostly demountable pushfit, but compression at the valve itself.
Demountable my arse. Like screws holding things together, they all come out but the last one.
And so it was. The demounting collar would not budge. Ended up just cutting the pipe.
And alarm bells should have sounded when one of the compression olives was under a yard of PTFE tape.
Tried to leave the backnuts and olives in place, and replace the valve body with a straight metal compression coupling, re-using the existing nuts and olives.
The suspect coupling would not stop weeping even with a bunch of PTFE.
Cut the pipe back behind the olives and used a new JG Pushfit fitting and all was well.
I can haz hot baths!