The Hydrant Flow Gauge is pre-calibrated to measure water flow from 2½"
hydrant nozzles in gallons per minute and pounds per square inch. It
will fit any 2½" nozzle opening without the use of tools.
To operate, remove the 2½" hydrant nozzle cap. Clean the thread to remove
grease or foreign matter. Open hydrant to flush any debris from the barrel.
Shut down hydrant. Assemble on the top of the nozzle thread with the blade
parallel to flow. Select a thread, then tighten thumb screw to securely hold
assembly on nozzle. Open hydrant fully. Purge the air from the bleeder by
turning counterclockwise. After water flows from bleeder, retighten. Read
pressure in pounds on inner ring, gallons per minute from outer ring.