Help to identify shower controller

[cotswoldmark]

Hi Forum - our shower for some reason is not providing a lot of hot water. Other taps are fine, so I think it's the valve or the hot/cold water adjustment ring; the challenge is getting to it though, there is no obvious way to remove the handle, covers etc.
Anyone able to identify this and have an idea on how to get into it?

 

[Deleted member 120897]

Try removing the white indice, there should be a screw located behind it. Shower looks similar to Deva, but some are similar in design anyway.

 

[cotswoldmark]

Try removing the white indice, there should be a screw located behind it. Shower looks similar to Deva, but some are similar in design anyway.

thanks for your help. I was able to get into the screw and undo it. However I also noted that there was a broken metal piece behind this (see pic). Even without this piece in place, turning the valve to maximum and minimum made no change to the water temp. Does anyone know if this piece can be replaced (if so what is it called)? Does it sound like a new valve is needed if there still is no hot water coming through?

 

[Ben-gee]

It’s a horseshoe washer and yes you need it!
It holds the valve in place so when the wax capsule lengthens it affects the hot/cold ratio. Without it the valve will just move in/out as a whole and temperature control is lost.

 

[Basher]

Otherwise known as a "circlip" or "E type circlip" or "E-clip"