"Doctor Evil" wrote in message
...

"Christian McArdle" wrote in message
t...

It can be I said "Having by-pass valves with condensing boilers is not
recommended and should be avoided". Sound advice. There are many ways
to
get around this. A heat bank/thermal store. Replace the internal pump
with
a Grundfos Alpha. Install an intermediate buffer store - a 40 litre
cylinder
heated by the boiler, with a fixed speed pump between boiler and pump
and
Grundfoss Alpha between the rads and buffer cylinder, etc, etc.

The DIYers know all the answers don't they.

All these solutions are a bit OTT when you
could just install the manufacturer's
recommended auto bypass valve, assuming
they haven't already incorporated one inside the case.

By-pass valves defeat the purpose of a condensing boiler, you have been
told
that


Having all the TRVs off tends to have the same effect. The purpose of
having a bypass in to ensure a flow is maintained through the boiler and to
cool hot-spots during the pump run-on.