"Fred" wrote in message
...
"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.
An auto by-pass will open when the TVRs close down. Best have a Grundfoss
Alpha pump and flow switch. The flow switch off the burner when the flow is
below a certain setting. The pump continues.
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