KB21 Service Manual Pub 09-14
95
Pressure & Flow Supply Test: Manual Control Valve
This test should be performed while the malfunction is occurring. This test is used when one or more
functions are inoperative (either constant or intermittent). This test will use the hydraulic schematic on
previous page for reference points.
1. If only one or some functions of valve are not working it is easiest to check the relief valve for that
section, it could be a relief valve or an O-ring seal of a relief valve. See the charts on the next page to
determine what relief pressures should be and if section has its own relief or uses a system relief.
2. If no function works, it is easiest to visually check main relief valve on control valve, it could be the
relief valve or an O-ring seal for the relief valve. If the relief is OK go on to next step.
-
tings.
caused by line restrictions. At 1800 rpm you should have 8 gpm and still 100 psi through
-
tion
pump section.
pressure gauge as you go, increasing pressure in 500-psi increments. There will be no need to ex-
ceed 2000 psi when doing this test. Gpm will drop when under pressure but should not drop below 6.8
section on tandem pump option.
6. If only one function of valve is not working it is easiest to visually check the relief valve for that sec-
tion, it could be a relief valve or an O-ring seal of a relief valve. If relief valve visually check OK, you
will need to test for pressure, go on to next step.
7. See the charts on the next page to determine what relief pressures should be if section has its own
relief or uses a system relief. This can be check by connecting a pressure gauge to the hose of the
cylinder function you are testing (A gauge of 5000 psi is recommended). The gauge should reach the
recommended check valve pressure if this relief checks OK the problem is in the cylinder itself, or the
cylinder or a pivot point could be in a bind.
s.
the
.
80 - A. Mechanical Control Valve
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