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UEN00245-02
H-7 Speed or power of boom is low
Trouble
• Speed or power of boom is low
Related
• Carry out all troubleshooting in power mode (P) of working mode.
information
Malfunction of right PPC
1
valve (boom circuit)
Malfunction of merge-divider
2
main EPC valve
Malfunction of merge-divider
3
LS-EPC valve
Malfunction of merge-divider
4
main valve
Malfunction of merge-divider
5
LS valve
Malfunction of boom control
6
valve (spool)
Possible
Malfunction of boom control
causes and
7
valve (pressure compensa-
standard value
tion valve)
in normal state
Malfunction of boom control
8
valve (regeneration valve)
Malfunction of boom control
9
valve (lock valve)
Malfunction or defective seal
10
of safety valve for lock valve
Malfunction or defective seal
11
of boom control valve (suc-
tion valve)
Malfunction or defective seal
12
of boom control valve
(safety-suction valve)
Malfunction of each control
13
valve (LS shuttle valve)
14 Defective boom cylinder
12
Cause
Standard value in normal state/Remarks on troubleshooting
a
Right work equipment control
Merge-divider main EPC valve may have malfunction. Check it
directly.
Merge-divider LS-EPC valve may have malfunction. Check it
directly.
Merge-divider main valve may have malfunction. Check it directly.
Merge-divider LS valve may have malfunction. Check it directly.
Spool of boom control valve may have malfunction. Check it
directly.
Pressure compensation valve of boom control valve may have mal-
function. Check it directly.
Regeneration valve of boom control valve may have malfunction.
Check it directly.
Lock valve of boom control valve may have malfunction. Check it
directly.
Safety valve for lock valve may have malfunction or defective seal.
Check it directly.
Suction valve of boom control valve may have malfunction or
defective seal. Check it directly.
Safety-suction valve of boom control valve may have malfunction or
defective seal. Check it directly.
LS shuttle valve of left travel control valve, bucket control valve, or
service control valve may have malfunction. Check it directly.
a
Right work equipment control
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
lever
Neutral
Boom raise
Boom lower
Prepare with engine stopped, then run engine at high idle and
carry out troubleshooting.
lever
Boom raise relief
40 Troubleshooting
PPC valve output pressure
0 MPa
2
{0 kg/cm
}
2.84 – 3.43 MPa
2
{29 – 35 kg/cm
}
Leakage from boom cylinder
20 cc/min
PC210, 230, 240-8
1
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Troubleshooting
