Toro Reelmaster 5510 Series, Service Manual

Page: 158 / 662

Lower the Cutting Units
When the joystick is moved to the lower position with the engine running, the
solenoid valve (SVRV) energizes along with solenoid valves (SV1) and (SV3).
The solenoid valve (SV2) is in its normally de-energized position, and directs
fluid flow to the piston end of the lift cylinders. The hydraulic pressure against
the piston side of the cylinder causes the shafts to extend, and lower the cutting
units. The piloted check valves in the lift control manifold are shifted by hydraulic
pressure to allow return flow from the extending lift cylinders. Fixed orifices in the
lift control manifold (CV1, CV4, CV5, and CV23) control the lowering speed by
providing a restriction for the return flow from the lift cylinders.
Because cutting unit weight assists in extending the lift cylinders when lowering
the cutting units, less hydraulic pressure is necessary during the cutting unit
lowering operation. Lift circuit lower relief valve (R7) allows lift circuit pressure to
be limited to 3,447 kPa (500 psi) while lowering the cutting units.
Note: Do not adjust the lift circuit lower relief valve (R7).
When the joystick is returned to the neutral (center) position, the solenoid valves
are de-energized and the lift cylinders (and cutting units) are held in the lowered
position.
Hydraulic System: Hydraulic Flow Diagrams (5610-D) Page 6–40 Reelmaster ® 5410/5510/5610 Series
15216SL Rev C