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6.3.3 Relief valve
The main relief valve is on the electro-hydraulic unit and limits the maximum working pressure.
6.3.4 Pilot operated holding valves
These valves are installed on every cylinder and will stop and lock every motion of the cylinder should any
pressure loss occur. Before starting operations it is necessary to check that these valves are perfectly
working, as follows:
• lift a load and raise the boom up to an angle of 45° upwards, with the boom sections partially extended
• switch the truck engine off push and pull repeatedly all the control switches: the load must remain still.
6.3.5 Safety devices’ sealing
Some safety devices or crane components can be sealed after setting during testing operations.
Such sealing can be only removed by the manufacturer or by an authorized workshop who will carry out a
new sealing after repairing according to Manufacturer’s specifications.
DANGER
The removal of sealing by non authorized personnel, or a sealing not complying to manufacturer
specifications results in an improper usage of the crane.
!
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