Manitowoc National Crane NBT30H-2, Service Manual

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HYDRAULIC SYSTEM NBT30H-2 SERVICE MANUAL
2-24
03-20-2019 Control # 613-06
6. If the pressure in previous step cannot be reached,
adjust the load sense relief valve on the main directional
valve (Figure 2-16). Turn adjusting screw clockwise a
half turn and tightened and repeat previous step until
pressure is reached.
7. Stop the engine and remove the diagnostic equipment.
Directional Control Valve
Lockout Pressure Adjustment
1. Install a gauge at the pump pressure gauge port GLS on
the pump (Figure 2-15).
2. Start engine and idle RPM.
3. Do not bring up the RCL system and feather into the
throttle bringing the engine to Full RPM.
4. The pressure gauge should read 7239 kPa ± 1185 (1050
PSI ±172).
5. If the pressure is not correct adjust the lockout pressure
reducing cartridge located in the lockout manifold
(Figure 2-17). Screw “in” to increase or “out” to decrease
to achieve the correct pressure.
6. Stop the engine and remove the diagnostic equipment.
Telescope Extend Pressure
1. Install a gauge at the pump pressure gauge port GP on
the pump (Figure 2-15).
2. If boom is not installed, remove hose from tele extend
port and plug the hose and cap the port before
proceeding to next step.
3. Start the engine
4. Idle RPM if the boom is attached and fully extend the
boom
5. Hold at end of stroke.
6. If no boom, activate boom out
7. Throttle up to full RPM.
8. The pressure should be 19650 ± 689 kPa
(2850 ± 100 psi).
9. Adjust the pressure relief cartridge located in the tele
relief valve (Figure 2-16). Screw in to increase or out to
decrease until correct pressure is achieved, and re-
tighten the locknut.
10. Stop the engine and remove the diagnostic equipment.
11. Reconnect hose to tele extend port if removed.
Trouble Diagnosis
The following chart lists malfunctions which may occur
during operation, the possible cause, and the possible
solution. These are not all inclusive but are designed to help
isolate the problem and should be checked before calling
Manitowoc Crane Care.
FIGURE 2-16
Load Sense
Relief Valve
Tele Extend
Port
Tele Extend
Relief
8730-2
FIGURE 2-17
Lockout Pressure
Reducing Cartridge
8737
Pilot Manifold
Valve