You can get a diaphragm from interparts part no:10/12480.un screw drain plug first un screw clamp on winter/sumer inlet then the screws around outer casing. I have just done mine and it is now giving me hot water again.ps.do not over tighten screws.
nigel crane
January 2011
Hello you will need the model of the medway super look on the data plate and you will find the gas council number this will identify the exact model.i use Thermagas spare center for all my parts they are brilliant open all day saturday unlike most spares companies also the lads noknow the products inside out they dont just shift boxes of spares the tec knowledge is amazing and sell all the appilances and pluming stuff as well tgive them a try 01257 275080