Delavan 4.00GPH, 80B (7) Düse

This is a Delavan oil nozzle, a precision consumable part that atomises fuel oil into a fine spray for complete combustion. The nozzle is fitted into the burner’s combustion head and connected to the oil pump via the high-pressure oil line. Parts of this type are selected by three parameters: flow rate (in USGPH at the reference pressure), spray angle, and spray pattern (hollow, solid, or semi-solid). All three must match the burner manufacturer’s data plate. A nozzle with the correct rating but a wrong pattern can cause sooting, pulsation, or unstable ignition; the same applies if the spray angle is not suited to the combustion head geometry. When replacing a nozzle of this class, verify the code against the existing part or the burner manual. The thread size is standard for domestic and light commercial oil burners. Because the nozzle is a wear item, it should be changed at the scheduled service interval or whenever combustion readings drift. Always handle the nozzle with care—debris or damage to the orifice will distort the spray cone.