On Sun, 18 Dec 2005 18:54:53 +0000, leveled wrote:

I have some small so called bleed vent things on upright pipes in my loft
.My heating pipes are in the loft. I was told they were auto air removers
,they are large egg cup size with a small plastic screw on top , how do
these work (if at all) Regards E

There's a float inside the chamber which closes off the vent at the top
when water gets into the chamber. If the dust cap's on tight it won't
automatically bleed (but will stop water escaping if the float sticks)