Goldacres Prairie Pro Operator's Manual page 97

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Boom yaw is controlled by a pair of hydraulic rams
and accumulators. Oil in these circuits flows through
the spool block mounted on the back of the boom
centre.
BEFORE YOU BEGIN
• Park the machine on a flat level surface, engage
the parking brake and chock the sprayer wheels.
• Start with the boom in the working (unfolded)
position.
YAW ANGLE ALIGNMENT PROCEDURE:
Yaw Bleed
Test Port
1. Wind out (counterclockwise) both the 'Yaw A'
and 'Yaw B' valves to open them fully.
2. Move the boom around by hand until it is sitting
perpendicular to the chassis of the machine.
3. Wind in (clockwise) both the 'Yaw A' and 'Yaw B'
valves to close them fully. The default yaw position
is now set.
YAW LINE AIR PURGE PROCEDURE:
• This procedure is typically only necessary when
the hydraulic yaw circuit has been opened, such as
when replacing a component e.g. hose.
1. Wind out (counterclockwise) the 'Yaw Bleed'
valve to open it fully.
2. Start the engine and then move the boom
around by hand for a minute or so to help force
air out of the hydraulic yaw circuit.
3. Wind in (clockwise) the 'Yaw Bleed' valve to close
it fully.
4. Shut down the engine.
Prairie Pro Operator's Manual MY19 - REV 2
t ent
Pressure
Reducing
Valve
Yaw B
Yaw A
YAW LINE PRESSURE SETTING PROCEDURE:
• The hydraulic yaw pressure setting determines
the effective stiffness of the yaw damping.
1. Connect a pressure gauge capable of reading up
to 3000 PSI or more to the test port.
2. Follow the "Before you begin" instructions and
start the engine.
3. The hydraulic system will build pressure when a
function is activated. Preferably engage 'Stage 1
Fold' OUT as the boom is already folded out and
will not move in a hazardous way.
4. Once pressure has built up fully, use the pressure
reducing valve to set it higher lower as necessary.
The target pressure for the 48 metre boom
is 1 PSI. Loosen the lock nut first and then
wind it in to increase pressure or wind it out to
decrease pressure.
NOTE: If the pressure is too high then wind
out (counterclockwise) the 'Yaw Bleed' valve to
reduce it in addition to the pressure reducing
valve. Then, close the 'Yaw Bleed' valve and check
the maximum pressure achieved again. Pressure
will not decrease on the gauge if only the
pressure reducing valve is wound out.
5. Re-tighten the lock nut on the pressure reducing
valve once the pressure is set.
6. Shut down the engine and disconnect the
pressure gauge.
Chapter 9 - Boom - 91