
Monarch 2.25GPH, 45PLP nozzle
This is an oil nozzle from Monarch, a precision consumable part that atomises fuel oil into a fine spray cone for complete combustion. It sits between the oil pump and the combustion head. The flow rate in gallons per hour (GPH), the spray angle, and the spray pattern (hollow, solid, or semi-solid) together determine how the flame sits in the combustion head and how it matches the air pattern from the burner's blast tube. When replacing a nozzle, all three parameters must match the burner data plate; correct GPH alone is not enough. A nozzle with the wrong pattern can cause sooting, pulsation, or unstable ignition even if the flow rate is correct. The thread and the reference pressure also need to correspond to the burner specification. This specific article is the Monarch 2.25GPH, 45PLP nozzle, catalogue article 732.892.102, manufacturer code 2.25GPH,45PLP, 732.892.102. It is identified by its flow rating and angle/pattern designation in the product name. As with any nozzle of this type, the exact GPH, angle, and pattern written on the part should be verified against the burner's requirements before installation.