how can i fix my raven combi boiler?

Hi Sharon, I had a similar problem with my combi which turned out to be a perished diaphragm that should cut off the heating circuit when hot water is drawn. This means you are heating radiators instead of the hot water, which explains why you are getting some hot water when the heating is on. It is not an expensive part but may cost a few quid to fit.

Glenno
April 2010