Toro Groundsmaster 5900 Series Service Manual page 127

Left Cutting Deck Lower
Cutting Deck Float
Groundsmaster ® 5900 & 5910
16227SL Rev B
To lower the left wing deck, the front of the left console switch is depressed to
act as an input to the slave TEC. The controller provides an electrical output to
solenoid valves S1, S3 and S4 in the steering/deck lift control manifold. The
energized solenoid valves shift to allow a passage for circuit oil flow to the rod
end of the left wing deck lift cylinder. Shifted S1 prevents oil flow from returning
directly to the traction charge circuit. Shifted S3 allows an oil path to the shaft
end of the lift cylinder to retract the lift cylinder and lower the left wing deck. Oil
from the retracting cylinder flows through orifice OR3 to control the drop speed of
the cutting deck. Flow is then directed through the shifted S4, counterbalance
valve (RV3) and then is routed to the traction charge circuit.
When the deck switch is released, the control manifold solenoids are
de−energized and the lift cylinder and left wing deck are held in position.
Cutting deck float allows the fully lowered cutting decks to follow ground surface
contours. Lift control manifold solenoid valves S4 (left deck), S6 (front deck)
and S9 (right deck) are energized when the decks are fully lowered. These
energized solenoids provide an oil passage to and from the lift cylinders to allow
cylinder and cutting deck movement while mowing. Counterbalance pressure
will affect deck float operation.
Note: If a deck is already fully lowered when the key switch is moved from OFF
to RUN, the deck will not be in float until the deck lift/lower switch is momentarily
pressed to lower.
Page 5–27 Hydraulic System: Hydraulic Flow Diagrams