Dover HEIL LIBERTY TP1L-SM-0520, Service Manual

Page: 63 / 136

Issued May 2020
Lift Arm
Copyright 2020, Heil Environmental
Printed in the U.S.A.
Lift Arm
57
LIFT CONTROL VALVE PRESSURE ADJUSTMENTS (CONTINUED)
B. Checking and Making Adjustments (Continued)
2. To check the main relief on the lift valve, dead head any function that has a higher set point - like lift retract or lift
raise, and hold that function while monitoring the pressure gauge. (Dead heading is when you extend or retract a
cylinder to its maximum mechanical limit, and continue to maintain pressure for that circuit.)
3. To make adjustments to the main relief, you will first need to loosen the jam nut with a 1-1/2” wrench.
4. To make the adjustment you will need a 1/2” hex wrench, or a socket with ratchet.
5. To check the lift raise and lift retract port relief valves, you will need to raise the main relief one 1/2 turn clockwise so
that it is high enough to allow you to see the 2500 psi.
6. Check all port reliefs by dead heading each function, one by one.
7. To make adjustments to the lift lower or lift raise port relief valves, you will need to loosen the jam nut with a 15/16”
wrench. Then make the adjustment with a slotted socket bit, or a large slotted screwdriver.
8. To make pressure adjustments to the lift extend, lift retract, grabber open, or grabber close port relief valves; you will
need to loosen the jam nuts with a 7/16” wrench. Then make the adjustments with a 1/8” wrench or socket with
ratchet.
9. After making pressure relief adjustments, you will need to bring the main relief setting back down to 2300 PSI. To do
this, view your pressure gauge while dead heading lift retract. Lower the main relief until the gauge reads 2300 PSI,
and then tighten the jam nut.
10.After making pressure adjustments, make sure that all port relief valve jam nuts are tight. Then clean up your work
area by removing the pressure gauge, replacing the dust cover over the gauge port, and wiping down the area.
C.To Place the Lift Arm In Automated Mode
1. Make sure the key switch is on.
2. The system power is on.
3. Then hold the grabber open and grabber close buttons at the same time, until the alarm stops sounding.