While you wait for answers, we may have found some information which could help you.
Click here for Saunier Duval F35eLow pressure below 1, Lockout on. won't rest?
What size spanner to free rad bleed valve?
My electric oil heated radiator isn’t heating up properly. ?
Efficiency of my oil heater?
How can I mend my Hyundai oil filled radiator?
Glen Dimplex Oil Filled Heater OFC2000 2KW?