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Gam plumb
Hi, I have had two recent minor 1 burners with the same problem, thick black soot with ppm off the scale, checking & adjusting oil pressure & air makes no difference, first occasion I tried new nozzle, motor, pump checked flue etc, I rigged up a temp oil supply, both were on thermocon boilers one with balanced flue & second on a conventional flue. After speaking to many other engineers each with there own diagnosis, I have not got to the route cause, any help gratefully received