Alpha E Tec Combi boiler. How do we know when to repressurise the expansion vessel??

[@markchristohperowen6806]

tap it with a screwdriver and listen? that doesnt mean it doesnt need checking. it gives you insight. no greae on schraders. leak test fluid, if its broken replace.

[@b1h2u3p4]

If lots of water coming out schrader means it gone the diaphram