Bomag BW 156 D-3 Service Manual page 75

Service Training
Charge pressure relief valve
The charge pressure relief valve is a direct acting valve with a fixed adjustment and belongs to the group
of safety elements in the closed circuit. This valve limits the pressure in the charge circuit to the value
determined by the setting of the valve (approx. 25 +/- 1 bar).
The charge circuit has the function to replace leakages and flushing quantities in the closed travel and
vibration circuits and to supply the necessary pilot oil for the controls on travel and vibration pumps, the
travel speed range selection and to release the multi-disc brakes in the travel system.
Since cooled ad filtered oil can only enter into the closed circuit on the low pressure side, the pressure
in the low pressure side is identical with the pressure in the charge circuit.
With the machine at standstill on level ground and the engine running, both sides of the closed circuit
are under charge pressure.
BW 156/177 D-3/PD-3 - D 15 -
BW 178/179 D-3/PD-3