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Operating Instructions
WARNING
Follow all safety and operating instructions provided with your high pressure water jet unit as well
as applicable local and OSHA standards. Always wear goggles, gloves and other safety attire.
Proper Orifice Selection
The O’Brien root cutter is supplied with two special bypass orifice grease fittings. One style must be
selected and screwed into the jet head for proper root cutter operation (see fig. 1). The orifice fittings
are color coded for easy identification. One black for 1” hose units and one plain for 3/4” hose units.
The 3/4” root cutter orifice is designed for units having flow capacities of 30-35 GPM (113.6 - 132.5
LPM) and the 1” root cutter orifice (black) is designed for units having flow capacities of 45-60 GPM
(170.3 - 227.1 LPM). These flows require operating pressure of 1200 PSI (80.5 bars) to 2000 PSI
(140 bars). The 3/4” root cutter hose requires the use of the reducing bushing (furnished) to be screwed
into the jet nozzle to accept a 3/4” hose fitting. After selection of the proper fitting(s) are made, screw
fitting(s) into jet nozzle
tight
(
NOTE:
Use thread lock if available).
DANGER
In no case should pressures greater that 2000 PSI (140 bars) be
applied to the root cutter unit. Damage to equipment or personal
injury including death could result.
Fig. 1
By-Pass Orifice Grease Fitting
Plain 3/4” Unit
Black 1” Unit
