Service Manual

Groundsmaster 4500 --D/4700--D Hydraulic SystemPage 4 -- 25
Mow Circuit
Hydraulic flow for the mow circuit is supplied by the first
two (2) sections of the gear pump. The first gear pump
section P1 supplies hydraulic flow to decks 5, 3 and 2
(also deck 7 on the GM 4700--D), while the second gear
pump section supplies decks 1 and 4 (also deck 6 on the
GM 4700--D).
A single deck control manifold is used to control flow
from the two (2) pump sections. The manifold includes
cartridge valves for control of each of the two (2) pump
circuits. Each manifold circuit is equipped with a sole-
noid controlled, proportional relief valve (PRV1/PRV2),
a logic cartridge (LC1/LC2) and a brake relief cartridge
(RV8/RV09). The Groundsmaster 4700--D deck man-
ifold includes additional cartridges to control hydraulic
flow for decks 6 and 7: an additional logic cartridge
(LC3/LC4), a solenoid valve (SV1/SV2) and an addition-
al brake relief cartridge (RV10/RV11).
PTO Disengaged
When the PTO switch is OFF (or if the decks are r aised),
the deck control manifold solenoid valves (PRV1 and
PRV2) are not energized, allowing hydraulic flow to by-
pass the deck motors through the manifold. Return oil
from the manifolds is routed to the oil cooler and oil filter.
PTO Engaged
When the PTO switch is turned ON with the decks low-
ered, the solenoid valves (PRV1 and PRV2) are ener-
gized with outputs from the TEC--5002 controller. The
energized valves shift to direct pump flow toward the
deck motors. As circuit pressure to the deck motors in-
creases, the brake relief cartridge (RV) opens which al-
lows an oil flow through the manifold orifice positioned
before the logic cartridge (LC). This flow creates a pres-
sure increase at the logic cartridge that will shift the logic
cartridge and allow oil return from the deck motors.
On the Groundsmaster 4700--D (Fig. 19), if deck 6 or
deck 7 is lowered and the PTO switch is ON, the deck
control manifold solenoid valve (SV1/SV2) will be ener-
gized by the TEC--5001 controller. This energized sole-
noid valve allows oil flow to the appropriate deck motor
as described above.
Maximum mow circuit pressure is limited at each deck
manifold circuit by the proportional relief valve
(PRV1/PRV2). The deck relief valve pressure is 3500
PSI (241 bar). Mow circuit pressure can be measured at
port G1 or G3 of the deck control manifold.
The brake relief and logic cartridges control the stopping
rate of the blades when the solenoid valves are de--en-
ergized as the PTO switch is turned OFF or if the decks
are raised (see Cutting Deck Blade Braking in this sec-
tion).
Figure 18
CUTTING DECK LOCATIONS
#4 #1 #5
#7#6 #3#2
Figure 19
3500
PSI
3500
PSI
1500
PSI
1500
PSI
1500
PSI
1500
PSI
P1
P2
T1
G1
PRV1
SV1
PRV2
SV2
LC1
LC4
LC3
M1
M2
M3
M4
M5
M6
M7
M8
RV11
RV09
RV10
T2
RV8
G4
G3
G6
G2
G5
LC2
FROM
TO DECKS
FROM
1&4
DECKS
1&4
TO DECKS
2, 3 & 5
TO DECK
6
FROM
DECK 6
FROM
DECKS
2, 3 & 5
TO DECK
7
FROM
DECK 7
GEAR
TO OIL
COOLER
FROM FAN
CONTROL
MANIFOLD
PUMP
FROM
GEAR
PUMP
DECK CONTROL MANIFOLD (GM4700--D)
PTO SWITCH ON AND #7 (RH) DECK RAISED
Hydraulic
System