Citytrac 4200
Citymaster 1200
Citycleaner
Service Documents
For internal use only
Status
March 2009
Page
57 of 108
5.4.3 Valve manifold function description
The oil is fed (46 l/min) from the gear pump ZP1 to connection P1 in the valve manifold. If valve Y4 (Pos.2) is not energised (CT 4200
mower drive; CM 1200 suction fan), the drive is switched off because the combined pressure control/circulation valve (Pos. 5.3.3)
DVPA-2 is opened via the pump side control line and the oil flows either via the bypass or through the oil cooler (Pos.205) and return
flow suction filter (Pos.204), depending on its temperature, back into the hydraulic oil tank. The circulating pressure is approx. 8 bar
with an oil temperature of 50°C. All the measurements for the drive must be taken at measuring point M1.
If valve Y4 (Pos.2) is energised (CT 4200 mower drive, CM 1200 suction fan), the drive is switched on. Y4 switches the connection of
the control line of the pressure control valve to the hydraulic oil tank. The force of the spring in the DBV takes effect and a maximum of
195 bar can be generated (measuring point M1)
Note: If the pressure control valve needs to be replaced, it is essential to set the pressure control valve to the prescribed
pressure (195 bar).
If the drive is switched off (Y4 is no longer energised), the control slide moves from valve Y4 back to its initial position and the
connection of the control line from pressure control valve
5.1 is reconnected to the hydraulic oil tank. The hydraulic oil can then flow
via the pressure control valve
again into the hydraulic oil tank. The circulation pressure is approx. 8 bar.
At the same time, the control line to pressure control valve
5.2 is closed by the control slide in Y4, the force of the spring in pressure
control valve
5.2 then takes effect so that pressure control valve
5.2 opens at 60 bar. This ensures that the front attachment device
(CT 4200 mower drive) comes to a stop within 7 seconds (work safety).
Note: If the pressure control valve needs to be replaced, it is essential that the pressure control valve is set to the prescribed
pressure (60 bar). In this case, the pressure control valve 5.1 and 5.2 must be swapped over for the adjustment process.
The oil from the gear pump ZP2 is fed via connection P2 to the valve manifold (approx. 36 l/min) up to the feed quantity distributor
(Pos.7). At this point, a constant 8 l/min. is extracted at connection Z for the steering. A further 28 l/min. are available at connection B
for the remaining functions in the manifold.
If no consumer is switched on (raise/lower front attachment support, pivot front attachment devices,
