"Mike Clarke" wrote in message
...

It is a modulating boiler and has
an internal bypass so it works OK but
I am conscious of the energy wasted
when all the TRVs are shut as the
boiler cuts in from time to time
to keep the water circulating inside
itself up to temperature.

Ah! Simple. Just fit a flowswitch on the return. When all TVRs are closed
the boiler will protect itself by opening its own by-pass and the flow
switch will simply turn the boiler off as there is no flow.

What is all the fuss on this thread. My, oh, my!