Jim Alexander wrote:

"Robert Laws" wrote in message
oups.com...

I know this has bee ndiscussed recently, but I don't think this
particular question has been answered.

When a direct heating combi boiler is used there can be a conflict
between a thermostatic shower mixer and the boiler's own temperature
control. Ideally, to get the most powerful shower, one would like the
boiler runnign aty full tilt, with the water flow adjusted so that the
temperature is nice.

Cannot answer your specific question but I have previously installed a
thermostatic bar type mixer (Screwfix or other Italian unbranded) on a
Combi installation and it has performed well. Since the temperature of the
combi delivery lags any imposed change in flow I would anyway have expected
a decent thermostatic mixer to cope.

Jim A

Just to add due to relevancy, my current bathroom refit, I have a
modulating combi, a pressure balancing/equalising valve and then a
triton tyne thermostatic bar mixer.
Since thermo valves have some delay in adjusting temp when another tap
is turned on, I thought the balancing valve would help. I have not yet
had a proper shower with this setup (still tiling !) but have tested
the shower with hair washes etc. I was a bit worried that the 3 things
in this equation would fight at some point, so its a bit of an
experiment, but has seemed OK so far. Worst case, out comes the
balancing valve ...
Cheers,
Simon.