In article , Broadback
wrote:

I have a Mira Excel shower running off a combi boiler. The shower
operates fine except that I find the flow control knob has become very
stiff to operate. I know that age (mine not the shower's) is a factor,
but even so I think it should be looser than it is. Any suggestions
please?

I've got a Mira shower running of a combi with similar symptoms. I don't
remember the model and I'm away from the house at the moment so can't
check but ISTR the manual suggested this could be due to the lack of an
expansion vessel in the HW supply. Never got round to following this up
though.

--
Mike Clarke