gas boiler vaillant vcw 242e, 282e - varying and loss of pressure?

OK i have the same problem and the answer is that your diaphragm has gone in your hot water pump....This takes a while to happen and gradually gets worse and worse taking a few month to stop working completely but the signs are there with it taking more and more time for the water to heat up until nothing happens at all. You can get around it by manually operating the pump valve (a little black rocker switch on top of the hot water valve). Open this manually using a screwdriver and check your water is heating, if so the diaphragm is damaged and needs replacing.

lee allsopp
October 2006