Hydraulic System; All Functions Inoperative; All System Sluggish; Platform Drifts Down - Skyjack SJ3219 Service Manual

Section 4 – Troubleshooting Information

4.3 Hydraulic System

4.3-1 All Functions Inoperative

1. Electric Motor DCM1 not engaged.
2. Pump P1 defective.

4.3-2 All System Sluggish

1. System Relief Valve R1 defective or not adjusted
properly.
2. Hydraulic pump P1 worn.

4.3-3 Platform Drifts Down

1. Defective or leaking Lift Cylinder(s) seals at the
gland.
2. Combination of stuck or defective Holding valve
2H-13.

4.3-4 Platform Lifts Slowly

1. Defective Lift valve 3H-14.
2. Lift Relief valve R2 is set incorrectly.
3. Defective Holding valve 2H-13.
4. Defective or plugged Lift Orifice O3.

4.3-5 Platform Does Not Lift

1. Defective Lift valve 3H-14.
2. Hydraulic oil level too low.
3. Machine overloaded and Overload Lights PL-1
and PL-2 on Emergency Stop buttons flashing.
4. Defective or plugged Lift Orifice O3.
5. Leaking or defective Lift cylinder C1.
212508ADA
97
Refer to electrical troubleshooting.
Check system pressures and Pump P1
functionality. Replace if defective.
Adjust valve. Replace if defective.
Check system pressure and flow from Pump P1.
Replace if defective.
Replace if damaged.
Note: There are no piston seals, just wear rings.
Check valves. Replace if defective.
Check valve. Replace if defective.
Check pressures. Replace if defective.
Check Holding valve 2H-13.
Replace if defective.
Clean Orifice. Replace if defective.
Check valve. Replace if defective.
Fully lower the platform. Fill hydraulic tank until
fluid is at or slightly above the top mark on the
sight glass.
Check machine limits and reduce weight as
required.
Refer to Electrical troubleshooting.
Clean Orifice. Replace if defective.
Check cylinder(s). Replace if defective.
Hydraulic System
SJ3215, SJ3219