The operation of the valve is identical to that of the B Series valve, however the high flow
selector switch has been removed. The High Flow operation is now contolled by the presence
of a High Flow enabled worktool being detected across pins F and G on the worktool electrical
connector. The high flow operation functions similar to the "standard flow" circuit, except that
the Machine ECM directs more current to the A1 or A2 solenoid valves, allowing the auxiliary
control spool to shift farther. When the thumbswitch is in the High Flow mode (maximum UP
or DOWN position), higher current is sent to the auxiliary solenoid. This will allow more
hydraulic oil flow to the auxiliary hydraulic circuit.
A dual stage load sensing relief valve is used to maintain system pressure. The system pressure
is increased during high flow operation through the "A1" or "A2" solenoid.
When only the high flow circuit is active, the Machine ECM will energize the XPS control
solenoid for the dual stage load sensing relief valve. The pressure cut-off spool within the
Pump Control Valve will now limit the maximum pressure.
The "C+" solenoid and "C-" solenoid provide pilot oil to shift the control spool for suppling oil
to the secondary auxiliary lines on the work tool lift arm. The "C+" and "C-" solenoids are
ON/OFF and controlled by switches on the work tool joystick Operation of these circuits will
cause the XPS control solenoid valve to de-energise, (should pins F and G be shorted together)
therefore reducing the max system pressure to the “standard” value. Upon releasing the
buttons, the ECM will re-energise the XPS control solenoid valve.
NOTE: Although the outer two envelopes on each end of the auxiliary/high flow spool
are identical on the schematic, more flow is allowed through the outermost envelopes.
SERV1833-01 - 81 - Text Reference
07/08