On Tue, 03 Jan 2006 11:06:05 GMT
tosser wrote:

John Rumm wrote:

There is a slight risk that the toilet cistern valve may not handle
the pressure rise (pretty unlikely)... you can assume the bath and
basin taps will be Ok since they are coping with mains pressure on
the hot one presumes.


OK, thanks. So I should be standing by the toilet cistern when I've
put mains pressure to it then, ready to turn the stopcock!


Just a note about an occurance here on Sunday last. The house was
built with a HW tank, but converted to a Combi-boilered mains pressure
system in the early 90's. Sometime, possibly later, I don't know when,
a new plastic toilet cistern (Fordham FlushPanel) was also fitted. I
also have hostital-style taps with 90 degree levers. I shut the cold
tap on the sink rather sharply, and heard the plastic diaphram valve in
the cistern explode! Well, in fact, one of the plastic parts inside had
been overtightened and the increased stress from the water hammer made
it split - our water pressure here is high, so a fountain of water from
the cistern resulted - fortunately the main stopcock was within reach
and only about a gallon of water overflowed. It's made me look at brass
ball valves with a whole new appreciation!

The moral of this story? You might have to wait a bit to be sure that
the mains pressure isn't going to result in a leak. However, I think my
experience is unusual.

R.