94
CONTROL VALVE
7c
Troubleshooting
7c- 4.
7c-4-1. Control valve - troubleshooting
No.
Symptom
Possible cause
Solution
1
Lifting or tilting
does not work
1 Failure of the pump or the coupling
Replace
2 Shortage of oil in the tank
Replenish
3 Breakage of Plunger spring
Replace
4 Failure of the hydraulic microswitch
Replace
2
Load with rated
capacity can not
be lifted
1 Failure of the relief valve or out of adjustment
Replace or
adjust
2 Failure of the pump
Replace
3
Lifting speed is
too slow.
1 Over-discharge of the battery
Charge battery
2 Short stroke of the plunger
Inspect valve
linkage
3 Damage of the packing in the cylinder
Replace
4 Rilief pressure is too low
Adjust
5 Damage of the packing of the plunger
Replace
6 Failure of the pump
Replace
7 Clogging of the oil filter
Clean/Replace
8 Hydraulic speed setting in the control unit is not
proper.
Adjust
4
Too much
drifting for lifting
or tilting
1 Damage of the packing of the plunger
Replace
2 Damage of the Cylinider or the Piston
Replace
3 Damage of the packing of Piston
Replace
5
Too much shock
when starting to
lift.
1 Activation timing of lift microswitches is improper.
Adjust
2 Failure of the relief valve
Replace
6
Oil leakage
1 Damage of O-ring or wiper ring.
Replace
2 Looseness of tie bolts of the hydraulic valve
Retighten
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