its a bristan artisan thermmostatic dual control shower recessed read maintenance but can not undo unscrew thermostatic cartridge

m vacher, May 2010

Hi Pete. I understand your annoyance. Getting the cartridge out of the Bristan Artisan bar-valve shower-mixer is not a well-designed operation.

But here's how.

Just stick it on the floor,
put your foot on it,
then attach a pair of grippers round the teeth that the control knob slips onto,
and then jerk back hard, anti-clockwise.

It might takes half a dozen pulls before it gives.

The new cartridges are made of plastic, so when putting them in make sure you tighten the gripper up hard before screwing the cartridge in so it is flush with the edge of the unit.

G Dawkins, August 2010

It's not necessarily limescale holding the cartridge in, I'm afraid.

I bought a Bristan Artisan shower mixer some time back and before I fitted it I wanted to be sure that it would open easily in the case of it developing an internal fault. Could I unscrew the thing? Like heck. And the silicone sealant was even seeping out of the opening into which the cartridge was screwed.

Took it back to the supplier, demanded my money back, and got something far simpler that can be easily opened - without taking the unit off the wall.

My advice: don't touch any of the Bristan bar-valves with screw-in cartridges. They're a nightmare to get out.

Stupid design. Not helpful to either plumber or householder.

Pete, July 2010

Un screw the retaining nut,

you'll need a decent adjustable spanner and its a case of carefully persuading it.

Limescale is your enemy here that is holding it in

Try supporting the shower with your shoulder as you lever the spanner rpound

Plumbstar Tom, May 2010

how do you fix it

m vacher, May 2010