Thanks for this John.
Having spent last night checking the oil flow (pipes and filters) I too am beginning to suspect that the key to the problem lies with the BM Control Unit. As I stated the thing looks like it used to have an electric top, but it has been removed by the last owners. The engineer who came round to service the Aga seemed reluctant to mess around with the high and low settings on the BM valve but did provide me with a short instruction and some advice. I am tempted to have a go at adjusting the grub screws myself. (I presume this is what you mean by "turn it down low", "turn it up high" John?). Even more so when I saw this web site: www.agadiyservice.co.uk
, where I can buy servicing instructions. I am an ex (Corgi registered) heating engineer so boilers do not scare me, although I know little about oil (but knowledge is increasing daily!).
My concerns are:
1) If I do decide to take on the administration and servicing of my Aga will I need expensive specialist tools?
2) Could my BM Control Unit be faulty and require replacing, rather than adjusting? What symptoms do faulty BM Control Units exhibit?
and the biggy...
3) Why should I need an electric top? I have been looking at a friends Aga which does not have an electric top. They have no complaints about the way it works. (Caveat, their Aga might not have been a vapourising sort - -I do not understand the import of vapourising yet).
Thanks for help so far. I am very grateful.