On Thu, 29 Sep 2005 00:21:22 +0100, Ed Sirett
wrote:

2) The boiler is not designed to take luke warm let alone hot water as
it's input.
One would hope the boiler can handle lukewarm water at least for a
couple of minutes. My loft sometimes reaches 50 celsius in the summer
and there will be a few litres of water in the pipe at possibly over
20 celsius.

If a house needs a secondary loop it also needs a grown up heating system
that will include a stored HW of some type (vented, unvented or thermal
store).
Having hot water in less than a second is a luxury rather than a
necessity. If it were easily possible with my new combi I would do it.
Since it seems not to be I shall be content with waiting 30 seconds!

Mr F.