Monarch 3.00GPH, 45PLP nozzle

Oil nozzles of this type are precision consumable parts that atomise fuel oil into a fine spray for complete combustion. The nozzle is mounted in the combustion head assembly, downstream of the oil pump and solenoid valve. Its flow rate, spray angle and spray pattern determine how the flame sits in the combustion head. A mismatch in any of these parameters — for example, a hollow-pattern nozzle where a solid-pattern is specified — can cause sooting, pulsation, unstable ignition or lockout. Selection is made against the burner data plate: flow rate in USGPH (or kg/h) at the reference pressure, spray angle typically between 30 and 80 degrees, pattern (hollow, solid, semi-solid) and thread size. When replacing such a nozzle, all three characteristics must match the original specification, not just the flow rating. Always check the burner setup sheet or the label on the appliance. The part number and manufacturer codes identify this particular nozzle but carry no information about its performance parameters; those must be verified from the marking on the nozzle itself or from the burner documentation.