On Mon, 8 Dec 2003 11:28:19 +0000 (UTC), Dan Winchester wrote:

I have a hot water cyclinder on the first floor with a header tank
directly above it - the two are combined as a single unit.

The air released by the heating of the water has to go somewhere, it
rises to the top of the HW cylinder. In a normal doomed top cylinder
it simply goes straight up the vent pipe. or will do on a properly
installed vent pipe...

With yours though it must collect at the top of the HW part. ISTR when
I had one of these combined thingies there was the equivalent of a
vent pipe that went from the top of the HW part to above the water
line in of the CW part. Is that clear? If not the air released only
has one way to go out through the taps. Well it's a theory, a theory
that is mine, mine that theory is...

--
Cheers
Dave. pam is missing e-mail