Anyone know how this type of auto air vent on a boiler works?
[IMG]
formatting link
bottom part of the left hand image is just some kind of cap that sits over the springy thing in the right hand picture, and is loosely restrained by the bar you have a top view of. It appears to be leaking water from the rubber seal round the edge but I wonder if that's because the air vent is blocked. I know they're cheap to replace, but having to take the pump out to do it makes it considerably less so. Any advice appreciated.