Genie GTH-636 Service Manual page 140

Section 4 • Repair Procedures
MANIFOLDS
How to Set the Boom System
Pilot Pressure
Note: Be sure that the hydraulic oil level is visible
in the inspection glass of the hydraulic tank.
1 GTH-636, GTH-644, GTH-842 and GTH-844:
Install a 0 to 3500 psi / 0 to 250 bar pressure
gauge into test port 3 at the side of the
hydraulic tank.
Note: There are four test ports at the hydraulic
tank. Test port 1 is closest to the tank; test port 4 is
farthest from the tank.
2 GTH-1048 and GTH-1056: Install a
0 to 3500 psi / 0 to 250 bar pressure gauge into
test port 5 at the side of the hydraulic tank.
Note: There are six test ports at the hydraulic tank.
Test port 1 is closest to the tank; test port 6 is
farthest from the tank.
GTH-1048
GTH-1056
a test port
b test port 4
c test port 3
d test port 1
a b c d
4 - 70 GTH-636 • GTH-644 • GTH-842 • GTH-844 • GTH-1048 • GTH-1056
GTH-636
GTH-644
GTH-842
GTH-844
6
b c d
3 Start the engine. Allow the engine to idle after
warming the engine to operating temperature.
4 Without operating any machine controls,
observe the reading on the pressure gauge.
Result:
GTH-636, GTH-644, GTH-842 and GTH-844:
The pressure gauge reads 500 psi / 34.5 bar.
The pressure setting is correct.
GTH-1048 and GTH-1056: The pressure
gauge reads 400 psi / 27.6 bar. The pressure
setting is correct.
Result:
GTH-636, GTH-644, GTH-842 and GTH-844:
The pressure gauge fails to read
500 psi / 34.5 bar. The pressure setting needs
to be adjusted. Continue to step 5.
GTH-1048 and GTH-1056: The pressure
gauge fails to read 500 psi / 34.5 bar. The
pressure setting needs to be adjusted. Continue
to step 5.
5 Locate the pilot pressure relief valve (schematic
item FB) of the control block on the front of the
hydraulic tank. Loosen the jam nut at the top of
the valve. Turn the adjustment screw clockwise
to increase the pressure or counterclockwise to
decrease the pressure. Tighten the jam nut and
repeat this procedure beginning with step 4.
a
FA
FB
FC
b
c
a hydraulic tank
b pilot pressure relief valve
c control block manifold
June 2007
REV C
Part No. 97487