Nozzles & Equipment
Automatic Nozzle
An automatic nozzle is a fog nozzle that holds a roughly constant tip pressure across a range of flows by moving an internal baffle. Pump it to its target tip pressure — about 100 psi — plus the line's friction loss.
Because the baffle self-adjusts, an automatic nozzle keeps making a good-looking stream even when it is starved, continuing to produce a usable cone down to roughly 75 psi. That convenience hides a trap: the stream looks right even when the line is under-pumped.
So with an automatic nozzle the panel, not the nozzle, is the source of truth. Set the pump discharge pressure from the math — target tip pressure plus friction loss plus elevation — and do not let a healthy-looking stream talk you out of it.