While you wait for answers, we may have found some information which could help you.
Click here for Heating Ravenheat Hot Changedravenheat csi 120 no hot water?
ravenheat csi 85(t) 780 series red light flashing?
csi 85t ravenheat no power at fan?
What is wrong with my ravenheat white star combination boiler,?
minimal hot water ?
Central heating but no hot water?