Steinen 0.55GPH, 60ST nozzle

An oil nozzle of this type is a precision component that atomises fuel oil into a fine spray cone, ensuring complete combustion. It is located at the end of the blast tube, directly in front of the ignition electrodes and within the combustion head. The nozzle is a consumable part; its performance degrades over time due to carbon deposits or wear, which can cause poor ignition, soot formation, or pulsating flame. When replacing a nozzle, the flow rate (given in GPH at a reference pressure), spray angle (here 60 degrees), and spray pattern (hollow, solid, or semi-solid) must all match the burner manufacturer’s specification. Using a nozzle with the correct flow rate but a different angle or pattern can shift the flame shape so that it impinges on the combustion head or heat exchanger, leading to unstable operation or excessive smoke. The spray pattern (ST in the designation refers to a standard hollow cone pattern) determines how the oil droplets are distributed. A hollow cone creates a donut-shaped flame, common for many light oil burners. The thread is a standard size for this class of nozzle, typically 1/8” BSP or NPT, but always verify against the original part. The nozzle is tightened to a specific torque; overtightening can distort the orifice, while undertightening may cause leakage or vibration. Nozzles should not be cleaned or re-drilled – they are intended for single-use replacement at service intervals or when the burner shows signs of poor combustion. The burner data plate always lists the correct nozzle specification, and that data is the only reliable reference for a replacement.