Installation, Operation and Maintenance Manual
MAN 689 Rev. 6
June 2021
35
Maintenance
Section 5: Maintenance
5.3
MHP Hydraulic Manual Override Maintenance
and Troubleshooting
5.3.1 Operation
(See the attached operating diagram, Figure 23).
The “MHP” hydraulic manual override is utilized, in connection with the actuator hydraulic
cylinder, for the manual operation of the actuators.
5.3.2
Manual operation
Selected by the hand operated directional control valve (D) has to be in its « MANUAL »
control position the operation (opening or closing) to be performed.
Actuate the handpump (P).
The relief valve (R) prevents that the oil pressure delivered by the handpump exceeds the
set value so to not damage the valve or the actuator.
!
WARNING
At the end of hydraulic MANUAL CONTROL, CLOSE the stop valve 351 to STOP the valve
position. To allow the AUTOMATIC CONTROL, OPEN the stop valve 351 and bring the
distributor lever in the ‘’AUTOMATIC CONTROL’’ position.
5.3.3
Remote Operation
To allow the actuator pneumatic operation the hand operated directional control valve (D)
has to be in its “REMOTE” control position: valve liver in its central position as shown by the
instructions plate.
The exceeding oil volume, corresponding to the hydraulic cylinder piston rod, flows into
the oil tank (Ot).
The relief valve (395) prevents that the oil pressure, into the hydraulic cylinder, exceeds a
set value.
