What are the likely causes of a build up of carbon deposits on the jet of an oil fired boiler?
The boiler was alternating between running roughly (nearly cutting out) and running smoothly. When I looked at the jet there was a large build up of carbon deposits. The boiler now runs smoothly with a new jet. As I have not had this problem before I would like to know whether there may be an underlying cause which needs attention. Is the carbon the cause or the result of the rough running? - or even both.