On 27/07/2011 19:14, harry wrote:
If you release boiler water. it instantly flashes off into steam.

Whether you could tell the difference as to whether steam or water was
present on opening the cock is an experiment I've never tried. (Never
had to)
I suppose theoretically there would be a different noise and volume of

Sounds like one of those things the average person would never be able
to differentiate but to someone who used the system all the time, they
would be able to tell the difference.

--
Graeme Wall
This account not read, substitute trains for rail.
Railway Miscellany at www.greywall.demon.co.uk/rail