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O’Brien Root Cutter Operation
After assembly of your O’Brien root cutter with skid and cutter blade as outlined in previous sections,
attach the high pressure hose. NOTE: If tubular tiger tail hose guide is used, slide it over the hose
before attaching hose to root cutter. Attach placement tool and lower root cutter unit into manhole and
position it at the pipe entrance with cutter blade facing in the direction of travel. NOTE: If possible,
cutting should always be done against the flow to allow debris to be carried back to the working manhole.
Start jet unit engine and turn on water pressure momentarily to allow root cutter to enter line several
feet. Turn off pressure and position hose guide/guard at pipe entrance. Tie safety rope to jet or clamp
in place, avoiding trip area. Mark hose top of manhole entrance with white waterproof tape.
Begin cleaning operation by running engine at low RPM. Back off or reduce output pressure at
regulator if unit is so equipped, and increase throttle setting on jet unit to operate at full RPM.
Adjust pressure regulator for maximum pressure (never exceeding 2000 psi). Feed root cutter
hose slowly into pipe allowing cutter to cut obstructions and to avoid jamming blade. Jamming of
cutter into obstruction could cause cutter and shaft to lock in the obstruction and the body of the
motor to rotate in the pipe, causing jet hose twist and damage. When hose is in the pipe, it should
be tight against the hose guide to avoid slack. Slacking of the hose indicates the root cutter has
encountered an obstruction. Immediately pull back on the hose by hand. Gradually feed root cutter
hose forward by hand allowing cutter to cut into and through obstruction. Use care to keep your body
well balanced and maintain stable footing when performing the above.
If root cutter does not penetrate blockage after several minutes, you may have encountered a
lateral or a collapsed pipe and should consider other options. Continued operation without penetration
can damage root cutter and/or blade or cause root cutter to lockup in pipe. After penetration is
made through a blockage, no slack should be felt or seen at hose. Continue feeding root cutter
slowly a few feet up pipe and if no slack is seen or felt on the hose, you are through blockage. For
every 2 to 3 feet of blockage, pull root cutter back to manhole to clear pipeline of debris. The
marking of white tape on the hose will indicate the root cutter distance of exit from the line. Do not
pull unit all the way into manhole at this time, but reduce water pressure and flow to root cutter to
prevent debris from washing into another pipe and clogging. If debris is not excessive, root cutter
may be allowed to advance further into pipeline as outlined above and the procedure continued
until complete line is cleaned. However, if debris is excessive with first run, pull root cutter toward
pipe entrance after turning down pressure to allow debris to build up in bottom of manhole. Turn off
water pressure and engine.
DANGER: Failure to turn off engine could result in inadvertent
activation of root cutter, resulting in serious bodily
injury.
