Well Jane, we are embarking onto unknown territory here. The Rayburn has several thermostats that prevent overheating - the most important one being a 'pump overrun stat'....this allows the water pump to keep running to disperse heat, even though the burner is off. This however doesn't apply to you, as your system is now empty. However, this stat is still active although there is no water in there...get my drift?
You say that the cooker can get up to temperature, and then it cuts off - thats fair enough. However, it should cut back in again when things cool down - but is the oven actually cold? What does the dial say? Cast iron retains heat for ages.
So, if you want the cooker to work, one or more of these stats has to be disabled - which can be as simple as removing them from their housing so they can't detect the temperature that the Rayburn is running at. However, this could cause massive overheating within the unit.
My own thoughts are: keep the heating burner fan running when you are cooking (this is electric, and separate from the oil pump and fan). This will keep hot gases going up the chimney. This could (possibly) give you thermostatic control back to the cooker. I still need to know what make of burner you have though. John
