On Tue, 26 Oct 2010 22:12:32 +0100, John wrote:

I have a Mira 415 and I needed to fit a flow reducer in the winter
to
allow the boiler to cope - it was delivering 12 litres a minute
and the
boiler struggled. It is now 9 litres a minute and it is fine

I realise now that your has a "flow" control (mine doesn't). Is the
problem there at lower flow rates?

Good test and I'd go with lack of capacity in the boiler especially
as it's only since the supply started getting colder that the problem
has appeared. Another thing is the OP not finding a "safety
interlock" that prevents the shower going above 38C or 43C (ie cold
to tepid) unless defeated. Though it doesn't look like this one has
such a "feature".

--
Cheers
Dave.