Mira Shower - goes cold periodically

[glrfin]

We've had a Mira Discovery Concentric Exposed Valve for a few months now. When it was originally fitted it ran off an old combi boiler and although the shower was new it would heat up and then go cold 3 or 4 times each shower, and each time it went cold the water power would increase and then slow again once the heat returned.
Thinking the problem was with the boiler, we've had a new 33kw vailant boiler fitted a month ago. The problem has reduced but not been solved completely. Now the shower may go cold only 1 or 2 times a shower.
Has anyone else had this problem, or any idea how to solve it?
(Original shower installer no longer lives in our region otherwise I would have asked him back.)

[stoneyboy]

glrfin,
The symptoms you are describing may be caused by debris in the shower valve, this may be limescale or may be because the pipework was not flushed when the shower was installed. Suggest the best solution to this problem is to get mira in to check it over - details here:
http://www.mirashowers.co.uk/contactus/ ... epairs.htm
end