On Thu, 20 Aug 2009 03:43:54 -0700 (PDT), chudford
wrote:

If not why don't you turn off the mains water and drain down the HW,
this would be the safest way.

So simple, why didn't I think of that? OTOH it would mean pouring a
whole hot tank away, which does seem wasteful. I haven't looked in the
airing cupboard yet, so I hope I might find a gate valve or something
in there. I have one in ours; are they fitted routinely,. if so, that
is promising but it does mean I won't get to buy a freezing kit!

BTW these kits: what do you reuse and what has to be replaced? Is the
can single use or can you use it to do more than one pipe before it
runs out?

Thanks.