While you wait for answers, we may have found some information which could help you.
Click here for Riello Burner Locks OutMy riello burner lights for about 12sec and then locks out?
Bleed a boiler?
Bleeding it after oil ran out?
How to increase air supply to Riello RDB Burner?
Fan Cage Making noise on a Riello 40 FS?
how can i mend my riello burner rdb1 483t50?