While you wait for answers, we may have found some information which could help you.
Click here for Ravenheat Combi Workspressure dropping on openning the hot water in my ravenheat csi 85 aboiler?
Ravenheat CSI 85 Red Light?
Faulty Worscester 35 CDi loosing pressure?
What is wrong with my ravenheat white star combination boiler,?
minimal hot water ?
ravenheat csi 120 no hot water?