I have a 30 year old BSA hotspur rotary type oil boiler. I manage to service it each year, but I would like to know what the ideal flamer colour should be?

Any estimate will do fine. I know I should check the emmisions side of things, but I can't, so any basic ideals please?

Martin H., November 2009

If the flame is yellow, there is too little air in the mix
If the flame is all blue, there is too much air.

Adjust the air intake damper under the motor until the flame is mostly blue with some yellow. This will change slightly when the boiler is hot, but should be about right.

pa12mm, October 2013

Almost all flames should be blue,if it is yellow there is not enough air supply.

anon, November 2009