jcb JS300 Service Manual page 714

Merged Flow
K Fig 16. ( T
For schematic,
This option allows the flow of both pumps to come together
where the attachment requires high oil flow.
When the merged option is selected, using the rocker
switch in the cab and the auxiliary pedal 53 is operated, the
hammer/auxiliary switch 45 is closed.
Once the pressure switch is closed the MECU will energise
solenoid A, B and C. Pilot pressure from the pedal will
select the auxiliary spool via port pa2 or pb2 depending on
the direction selected. Pilot pressure from the pedal also
crosses solenoid B which is now energised and sends a
signal to port pcc of the main control valve and selects the
merge spool.
Solenoid A is selected and allows pressure from the cab
manifold to cross and select the merge valve 47.
Solenoid C is selected and allows the spools of the
hammer/auxiliary changeover valve 27 to drain to tank and
select the auxiliary position.
Oil flow from pump 1 is available at the now selected
auxiliary spool. Flow from pump 2 is blocked at the merge
spool. Pump 2 oil then exits the valve block at P3. It
crosses the selected merge valve 47, enters the valve
block at P4 and merges with oil flow from pump 1. Both
pump flows cross the
changeover valve 27 to operate the attachment.
E-53
E-54).
selected hammer/auxiliary
9813/5100-1
Section E - Hydraulics
Hydraulic System
Hydraulic Operation and Schematics
E-53