On Mon, 28 Feb 2005 16:25:02 +0000, Mark
wrote:

snip
My original plan was (when I'm ready) to pour the sludge remover (and later
the inhibitor) into the tank in the loft but if it does, indeed, also feed
the domestic hot water then I guess that's a no-no, so just how do you get
it in there?

Do you actually have one or two header tanks in the loft? If you just
have one large tank you may have a Primatic cylinder and you cannot
use inhibitor in case your DHW gets contaminated.

Mark

This is close to my own problem, so I thought I'd ask here.

I have a single tank in the roof. The central heating pump has two
automatic valves below it - one controls the ch and the other is on a
pipe to the hot water cylinder. The whole thing is powered by a
Potterton wall mounted gas boiler.

The central heating alone works fine - all radiators get hot. But the
hot water, when set on the same twice-a-day timer as the central
heating, boils. Atleast, I think it's boiling - there's a sudden rush
of air - pretty alarming - from the cylinder, which then vents into
the roof tank.

Where does the air come from and how can I stop it?