IMM wrote:

Many combis have a separate heat exchanger for the hot water side
anyway.


I few don't and the main gas heat exchanger has cold fresh water running
through it. It is designed to cop with excessive low temperatures.

Tis why I say "many" and not "all"....

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/