Last year I replaced a Bottle Air Vent in my airing cupboard (small 3" brass), as it was leaking. Today there is another similar leak, but in a differnt component. This time it's a larger steel component (about 6" high, 2" wide). It's got what looks like a pressure-release valve on top, out of which small amounts of blackened-water mist is spraying (though, bizarrely(?), only the water-heating system is currently on... the central-heating system is off).
As you can guess, I'm no expert! But is the above sufficient info to advise what this element this, and how easy it is to replace? The Bottle Air Vent was simple, as it simply screwed into a one-way valve, but this item is in the middle of a 22mm horizontal pipe run, rather than terminating at the end of a vertical pipe. (It's a 9 year old non-combi non-cold-water-tank hot-cyclinder system.)
Many thanks,
Andy
