While you wait for answers, we may have found some information which could help you.
Click here for Type Oil RadiatorEfficiency of my oil heater?
What size spanner to free rad bleed valve?
Oil filled radiator won’t stop clicking?
Where can I get a manual for my ritetemp oil heater ?
Low pressure below 1, Lockout on. won't rest?
Sorry the make is dimplex model FC2009Ti?