Multiva Optima T Series, Operation And Maintenance Manual, Page: 13 / 41

9
Troubleshooting in the event that the side sections cannot be raised,
Optima T500 - T700 :
Feel whether the pressure reaches the hoses of the side sections' lifting cylinders when the side sections
are raised.
•
There is pressure -> Check that the hydraulic return connector is properly attached to the
tractor and that the hoses are not pinched anywhere. Quick connectors are not always
compatible with the tractor's connectors. Also test in another hydraulic return. Change another
quick connector to the hose.
•
No pressure -> Lift the harrow up to the transport position. Check whether the selector valve
spindles are moving. The spindles can be moved manually by twisting their actuator bar. Check
whether the actuator bar of the selector valves is properly attached and that it is not kinked. If
the levelling board is working also when the harrow is raised up, the problem is that the
spindles of the selector valves have not moved.
3.5. Operating principle of the front levelling board and depth adjustment hydraulics
The front levelling boards and the depth adjustment in models
equipped with fully hydraulic depth adjustment are operated by
three series-connected cylinders. The series-connection of
cylinders means that the oil flows from the piston side of one
cylinder to the rod side of the other cylinder. The oil only flows
through the tractor's valve to the first and last cylinder. All the
cylinders in the series are of different sizes, so that the oil volume
of the piston side corresponds to the volume of the next
cylinder’s rod side. Both the levelling board and depth
adjustment circuits have a double operated pilot valve that keeps
the working depth set even in the case that the valve of the
tractor leaks.
3.6. Synchronizing the cylinders
Series-connected cylinders must be set to the same level for them to work precisely.
Cylinders are synchronized by fully extending the cylinder rods using tractor hydraulics and maintaining
the pressure for about 30 seconds, and running the motor on low rpm. When the cylinder rod is fully
out, the oil can flow through a small opening past the piston to the next cylinder. Hydraulic oil flows
through all cylinders in the circuit, setting them to the same level and bleeding possible air out from the
system. Moving the cylinders back and forth will not synchronize them.
Synchronizing of depth and levelling board cylinders must always be carried out at the beginning of an
operation period. And always after changing a cylinder or a hydraulic hose to these circuits. Depth
adjustment cylinders must be synchronized at times also during tillage keeping the pressure on for a
few seconds.