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