Telescope Cylinder Charge Valve Manifold (If Equipped); Description; Maintenance; Valve - Manitowoc Grove RT765E-2 Service And Maintenance Manual

HYDRAULIC SYSTEM
TELESCOPE CYLINDER CHARGE VALVE
MANIFOLD (IF EQUIPPED)

Description

The telescope cylinder charge valve manifold is used in the
telescope cylinder charge system. The charge valve
manifold is mounted to the stiffener bracket, which is located
behind the swivel, that connects the two vertical sections of
the turret together (1, Figure 2-33).
The charge valve manifold (Figure 2-34) consists of a
manifold (1); a spring offset, solenoid controlled, two-way
control valve with integral check valve (2); a pressure
reducing valve (3) set to 13.8 bar (200 psi); two check valves
(4); and a normally-closed pressure switch (5).
The telescope cylinder charge valve manifold prevents the
boom from retracting due to thermal contraction of the oil in
the telescope cylinders under certain circumstances (refer to
Lock the retract cable adjustments with the jam nut., page 4-
17 for more detailed information). The charge valve manifold
does this by supplying oil to the telescope cylinder extend
circuits when the boom is elevated above 35 degrees. The
solenoid valve (2) is energized by the LMI when the boom
angle is greater than 35 degrees, allowing oil to flow through
the pressure reducing valve (3) and on to the telescope
extend circuits. Pressure in the telescope extend circuits is
maintained by the two check valves (4). The normally-closed
pressure switch (5) is plumbed into the charge valve
manifold and is used to alert the operator by way of a buzzer
and warning indicator if the pressure in the telescope
cylinder charge system is less than approximately 6.9 bar
(100 psi). For a schematic of the telescope cylinder charge
system, refer to Figure 2-35.
2-58

Maintenance

Removal
1.
2.
3.
Installation
1.
2.
3.
4.
5.
Published 9-04-2014, Control # 422-08
RT765E-2 SERVICE MANUAL
1
8020-1
Tag and disconnect the electrical connectors to the

valve.

Tag and disconnect the hydraulic hoses from the valve.
Cap or plug the lines and ports.
Remove the capscrews, nuts and washers securing the
valve to the turret bracket. Remove the valve.
Secure the valve to the crane with the capscrews, nuts
and washers.
Connect the hydraulic hoses to the ports on the valve as
tagged during removal.
Connect the electrical connectors to the valve as tagged
during removal.
Elevate boom above 35 degrees and ensure buzzer
does not sound and telescope cylinder charge indicator
does not illuminate.
Check valve and hoses for leaks. Make repairs as
needed.
FIGURE 2-33