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OPERATION
1) Insert and secure the Line Gauge threads into the inlet of the Pitotless Nozzle Threaded.
2) Insert and secure the threaded outlet of the Pitotless Nozzle into the swivel coupling of the differential chamber.
Line up the gauge ports of the differential chamber and Pitotless Nozzle so that they are parallel to each other.
3) Attach the discharge valve to the outlet-end (downstream-end) of the In-Line Pitotless Nozzle. Close the
discharge valve.
4) Secure the female swivel coupling of the In-line Pitotless Nozzle assembly to the water source. You can attach
the unit to a 2 ½” valve, a valve larger than 2 ½” by using adapters, or the end of a secured hose.
5) Attach the two gauge tubes to the differential gauge by inserting the free tube-ends into the push-to-connect
tube fittings on the differential gauge.
6) Attach the opposite ends of the gauge tubes to their respective gauge port connections on the differential
chamber and the Pitotless Nozzle. Connect the “High Pressure” side to the Pitotless Nozzle. Connect the “Low
Pressure” side to the differential chamber. Rotate the In-line Pitotless Nozzle so that the differential gauge can
be viewed easily.
7) Before flowing water verify that the discharge valve is fully closed and all connections are fastened securely. Any
leakage can affect readings. Slowly open the water source when ready. Allow the differential chamber to
completely fill with water and become pressurized.
8) Slowly open the discharge valve to the desired flow rate or to fully open. The differential gauge displays the
differential pressure. Use the appropriate flow chart to convert the pressure reading (psi) to flow-rate (GPM).
9) When the test is complete, close the water source and the discharge valve.
Note: All connections in this assembly must be water-tight. Any leakage can affect readings.
FLOW CHARTS
Verify the correct flow chart is used. It should have the correct size and the “In-line Pitotless Nozzle” logo in the
title. Additional copies are available at: www.HoseMonster.com/literature.html. The pressure readings on the
chart are in net psi. Net psi, also known as differential pressure, is the difference between the upstream
pressure and the downstream pressure.
MAINTENANCE
The female quick disconnect fittings. Apply lubricant or WD-40 for stainless steel or brass fittings as necessary
to prevent corrosion, and then wipe down with a cloth. The gauge port on the Pitotless Nozzle and differential
chamber are assembled with a ¼” nipple and a female quick disconnect coupling. The female quick disconnect
coupling can be removed, but the ¼” nipple cannot. Use a hold-back when changing out the female quick
disconnect coupling. Apply thread tape (not thread-locking sealant) on the male end of the nipple to re-install
the female quick disconnect coupling. Contact Hydro Flow Products, Inc. customer service if repair is needed.
Differential Gauge. For operation and battery replacement information, refer to the manufacturer’s
instructions, which are included and on the back-side of the unit. This gauge is not field serviceable. Calibration
to NIST standard is available through Hydro Flow Products. Contact HFP if service is needed.
The Line Gauge. It is recommended that analog gauges be certified and calibrated annually. Calibration to NIST
standard is available through us. Contact Hydro Flow Products, Inc. if service is needed.
Pitotless Nozzle and Differential Chamber. Wipe down the product with a damp rag after each use to remove
dirt and debris.
