Abstract: A burner block valve assembly for supplying oil and steam selectively to a main burner or stand-by burner when the main burner is being repaired or replaced includes a valve plug rotatably disposed in the valve body and rotatable between a main burner ignition position, an intermediate joint burner ignition position and a stand-by burner ignition position wherein steam and oil are routed from supply lines to the burners through two levels of passages, the valve plug including a first chordal slot adapted to route oil to the first level from an oil supply line directly to the main burner in the main burner ignition position, jointly to the main burner and the stand-by burner in the joint burner ignition position, and directly to the stand-by burner in the stand-by burner ignition position, the valve plug further including a second chordal slot adapted to route steam to the second level from a steam supply line directly to the main burner in the main burner ignition position, jointly to steam supply to both bur

Abstract: A burner block valve assembly for controlling the flow of oil and steam to a steam atomized oil burner which includes a tapered valve plug rotatable in a tapered bore of a valve body between an open burner ignited position and a closed burner extinguished position, the valve body including upper and lower diametrical ports having inlets respectively connected to an oil source and a steam source, and outlets commonly connected to the oil burner. Passages in the valve plug directly connect respective inlets and outlets in the open position to provide atomizing steam and oil to the burner tip, the steam passage including circumferential offset passage which provide steam flow to the burner tip in advance of oil flow as the valve plug is rotated to the open position thereby assuring atomizing steam prior to initial oil flow.