While you wait for answers, we may have found some information which could help you.
Success
Message
How to increase air supply to Riello RDB Burner?
My riello burner lights for about 12sec and then locks out?
how can i mend my riello burner rdb1 483t50?
My Riello 40 loses it prime ?
Riello 40 Burner problem?
can you fix the pump on a riello40?
Oil not reaching burner?
Bleeding it after oil ran out?
Bleed a boiler?
Fan Cage Making noise on a Riello 40 FS?
riello 40 starts, runs fine then stops. ?
Burner not working ?