We may have found other answers which could help you.
Click here for Boiler Central Heating Plumbing
RAVENHEAT RSF84T CUTING IN & OUT?
Ravenheat HE85T - no central heating, water working fine though?
Air switch on ravenheat csi system a?
I have the same problem did you get an answer?
ravenheat h85t looses pressure on ch only?
ravenheat ls 80t?