Dover HEIL LIBERTY TP1L-SM-0520, Service Manual

Page: 66 / 136

Issued May 2020
Lift Arm Copyright 2020, Heil Environmental
Printed in the U.S.A.
Lift Arm
60
RELIEF VALVE ADJUSTMENT
Follow these steps to set the main relief valve.
A. Tools Required
Quantity Tool
1 Personal protective equipment
1 Pressure gauge (0-5000)
1 1-1/2" Wrench
1 15/16" Wrench
1 7/16" Wrench
1 1/8" Wrench
1 1/2" Hex Wrench
1 Wire cutters
1 Slotted Screwdriver
1 Replacement seal
B. Before Making Adjustments
1. MAKE SURE the unit is on flat, stable ground and apply the parking brake and chock the wheels.
2. MAKE SURE the area around the unit is clear of all unnecessary people before you operate the controls.
3. Connect an approved pressure gauge to the unit’s hydraulic circuit where it will read the relief pressure.
4. Make sure the hydraulic oil tank is full.
5. Start the unit.
6. Activate and hold the hydraulic function that activates the hydraulic relief circuit to heat the oil.
a. Units with Shur-Lock systems must use the tailgate lock function.
b. Rear loaders must use the ejector retract function.
7. Every two minutes, cycle the ejector cylinder function to mix the hot oil.
8. Continue steps 6 and 7 until the oil temperature thermometer on the oil tank reads a minimum 140 ° to a maximum
160°.
9. Adjust the relief pressure.
a. Loosen the main relief valve jam nut using the 1-1/8” open end wrench.
b. Rotate and hold tailgate lower switch (on outside control box).
c. Read the pressure gauge, it should be 2500 +/- 100 PSI.
d. Turn the adjusting screw OUT (counter clockwise) to decrease the pressure or turn the screw IN (clockwise) to
increase the pressure.
e. Tighten the jam nut when the pressure is 2500 +/- 100 PSI.