Lobster wrote:

The limiting factor is not the freezing kit - it works 100%
effectively - but rather your plumbing ability/reliability: the
freezing kit will block the pipework for a matter of minutes
SNIP
Have never had the guts to use one myself. Once watched a pro do it
(successfully!) on a live water main, which I would find seriously
scary!

I've only used one once on a mains supply and it worked a treat. Rather
than a few mins, the water was off for a good 20 mins - we had to wait to
fill the kettle!

Dave