IX. System Dump Pressure
Return circuit pressure test is a check of the back pressure valve in the return line to the main hydraulic tank.
Pressure can only be tested with a definite return flow to the tank. When no functions are being operated, flow
will not exist in this line. Check this pressure only if a problem with the back pressure valve is suspected.
Install a 1000 PSI gauge in the test port for the return circuit. This test port is located in the boom/propel control
valve inlet section.
See Figure 9.
Running engine at full RPM, place bucket on the ground with the boom fully
extended. Raise and retract boom of the same time and read pressure on gauge. It should read 100-220 PSI.
There is no pressure adjustment for this circuit. Replacement of the spring or plunger in the backpressure check
valve is required if pressure is not to specifications. The backpressure check valve is located in the main return
line to the hydraulic reservoir.
FIGURE 9
RETURN CIRCUIT TEST PORT
1.
2.
Return Pressure
Test Port
Form No. 29705 3/99
14
Содержание XL4000
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Страница 305: ...GRADALL h y d r a u l i c e x c a v a t o r s XL 4000 5000 CENTER PIN REBUILD Form No 20026 Part No 2460 4164 ...