I have got a Vaillant boiler model no VUW 242 EH and need to change the diaphragm on the diverter valve. Is it possible to just drop the bottom part of the valve and do this in situ and if so anything to do first (drain water) and afterwards (get air locks out) and if so how.Many thanks for any replies.
That would probably be the water section diaphragm not the diverter valve (but you would know), either way, it's easier to take the valve out completely.