While you wait for answers, we may have found some information which could help you.
Click here for Replace Combi Boilerravenheat csi 85 b (t) hot water no central heating?
minimal hot water ?
Central heating but no hot water?
how can i ignite the pilot light on a ravenheat boiler?
csi 85t ravenheat no power at fan?
Faulty Ravenheat condensing boiler?