While you wait for answers, we may have found some information which could help you.
Click here for Hot Water Demandravenheat csi 85 b (t) hot water no central heating?
ravenheat csi 85(t) 780 series red light flashing?
csi 85t ravenheat no power at fan?
Faulty Worscester 35 CDi loosing pressure?
pressure dropping on openning the hot water in my ravenheat csi 85 aboiler?
Faulty Ravenheat condensing boiler?