JLG 20VP (3120728) Service Manual - Manual (Page 15)

SECTION 1 - SPECIFICATIONS
3120728 – JLG Lift – 1-3
1.6 HYDRAULIC PRESSURE ADJUSTMENT
Adjust system pressure so that platform will raise with
rated capacity in platform.
The following are recommended factory pressure set-
tings;
VP10,VP15 –1000 psi
VP20 – 2500 psi
Turning adjustment screw clockwise increases system
pressure, turning screw counterclockwise decreases
system pressure.
Make pressure adjustment with oil at normal operating
temperature. If pressure is set when oil is cold, platform
may not raise rated load after oil has warmed.
ONLY OPEN HYDRAULIC SYSTEM LINES WITH THE MAST LOW-
ERED TO RELIEVE PRESSURE IN THE SYSTEM. CAREFULLY
LOOSEN REQUIRED FITTINGS, WEAR SAFETY PROTECTION
EQUIPMENT WHEN WORKING WITH HYDRAULIC SYSTEMS.
Connect pressure gauge as shown in Figure 1-2., Hydrau-
lic Pressure Gauge Installation.
Select a T-Fitting to exactly match the thread size of the
pump (.562 x 18 THD), pressure line (.562 x 18 THD) and
gauge fitting as required.
1.7 CYLINDER SPECIFICATIONS
NOTE: All dimensions are given in inches (in), with the met-
ric equivalent, centimeters (cm), given in parenthe-
ses.
1.8 SERIAL NUMBER LOCATION
For machine identification, a serial number plate is affixed
to the machine. The plate is located on the back of the
mast, just above the mast support bracket.
Figure 1-1. Hydraulic Pressure Setting - Adjustment
Screw Located at Base of Pump Motor
(Remove Hex Head Cap as Shown)
PRESSURE
ADJUSTMENT
SCREW
ADJUSTMENT
SCREW CAP
Figure 1-2. Hydraulic Pressure Gauge Installation.
Table 1-5. Cylinder Specifications
DESCRIPTION
BORE
in./(cm)
STROKE
in./(cm)
ROD DIA.
in./(cm)
Lift Cylinder -
10VP 1.50
(3.81)
54.50
(138.43)
1.125
(2.86)
Lift Cylinder -
15VP 1.50
(3.81)
54.50
(138.43)
1.125
(2.86)
Lift Cylinder -
20VP 1.50
(3.81)
54.50
(138.43)
1.125
(2.86)
EXTEND
LINE
RETURN
LINE
PRESSURE
GAUGE
REPLACE ELBOW
WITH A T-FITTING
TO CONNECT
PRESSURE GAUGE
HERE