While you wait for answers, we may have found some information which could help you.
Click here for Fault Valve Combi Boilerravenheat csi 85(t) 780 series red light flashing?
minimal hot water ?
pressure dropping on openning the hot water in my ravenheat csi 85 aboiler?
ravenheat csi 120 no hot water?
Central heating but no hot water?
how can i ignite the pilot light on a ravenheat boiler?