Vokera Excell 80sp?

hi there we are getting heating and hot water but the water is not costant it will not fill a bath it is cold then hot we have to turn the water pressure down to get any hot water at all we have changed the diaphram in one of the valves but made no difference although it was perished any ideas what we should be looking at. kind regards mr cox.

ronald cox
January 2006

it sounds very much like the diaphram in the changeover valve

et
May 2005