Anyone got any experience and opinion on Viessmann boilers with or without weather compensation?
We've currently got a seven year old Worcester Bosch boiler (not combi) and the heat exchanger seems to be starting to shed a grey (aluminium?) powder into the condensate stream. It's also locking out increasingly regularly due, we think, to overheating. There's some kettling to be heard...
Options when it finally fails are either replace the heat exchanger, or replace the boiler with one that doesn't eat its heat exchanger. Viessmann had been suggested as it's all stainless steel. Weather compensation would be nice, though not if it's £silly.