Steve Firth wrote:
Malcolm wrote:

That's a good point that I'd fogotten about so that risk needs to
be added to the vented tank side of the equation. After all, if
you've no loft tank then that can't happen. I wonder how how many
deaths have resulted from this? Not a lot I'll wager but then
probably not too many people have been killed in the UK by unvented
cylinders either.

I seem to remember the recent infamous one (baby died on first day in
new property IIRC) didn't have the cut out switch in the immersion
so one failure and the plastic header tank gave way.

My recollection was that the vent from the safety relief valve

?

IIRC it was a vented cylinder that just boiled over through the
expansion/vent pipe into the loft tank. Don't think there was any "safety
relief valve" other than the open pipe. In fact, I think any sort of valve
on an open vented system is illegal.

had
been lead into the plastic cold water storage tank and that when the
immersion failed on hot water was dumped into the cold tank, causing
the tank to collapse and scald the baby in the room below.

That bit's certainly right.

Tim