Bar Mixer Shower Suddenly stopped working

[ashtonjay]

I fitted a Bar mixer shower for a woman about 4 months ago when i did her complete bathroom
she called me yesterday and said all of a sudden the shower isnt even dribbling when she puts it on
& sometimes its comes on long enough for a shower but the on/off know seems to be making a whining sound

if i remember its on/off on the left (quarter turn)
& temp on the right

any ideas fellas?

cheers

 

[JCplumb]

Is this the same bar mixer as your other post?

 

[ashtonjay]

yeah,sorry i forgot id posted before

cheers