RITE-HITE LEVEL-RITE HL-800 Series, Manual

Page: 27 / 48

HL-800 HYDRAULIC DOCK LEVELER
Pub. No. 1167-R2 - April 2003
27
TROUBLESHOOTING - CONTINUED
Problem Probable Cause Solution
6. Platform does not lower. a. Hydraulic fluid level is low. a. Check oil level when the unit is held
open with the maint. support. See
Figure 19. Refill if necessary. Do not
exceed maximum oil level indicated by
the “Oil Level” decal on the reservoir.
b. Velocity fuse has locked up due b. Attempt to raise unit to unlock the
to air trapped in the system. velocity fuse. Cycle unit (5 to 10 times)
until velocity fuse no longer locks up.
c. Velocity fuse has locked up due c. Loosen the shuttle valve adjustment
to a misadjusted shuttle valve. screw and cycle unit (5 to 10 times)
until velocity fuse no longer locks up.
d. Velocity fuse has locked up d. Remove weight and cycle unit (5 to 10
because of weight on the times) until velocity fuse no longer
platform. locks up.
e. Debris is lodged on or around e. Check for and remove any lodged
the leveler. materials on or around the leveler.
f. The power unit did not shut off, f. Verify that the ARTD actuator is
causing the platform to remain functioning properly.
in the fully raised position. Verify that ARTD and restrictor limit
switches are functional.
g. Debris in the hydraulic system. g. Consult factory.
7. Platform raises very slowly. a. Weight on top of platform. a. Remove weight from platform.
b. Hydraulic fluid level is low. b. Check oil level when the unit is held
open with the maint. support. See
Figure 19. Refill if necessary. Do not
exceed maximum oil level indicated by
the “Oil Level” decal on the reservoir.
c. System leak. c. Check hoses, fittings, valves and
power unit for leaks.
d. Shuttle valve is not adjusted d. Readjust shuttle valve.
properly.
e. Adjustable system relief valve e. Readjust until the relief pressure
pressure is set too low. is 1200 psi.
f. Low voltage. f. Verify ±10% nominal voltage while unit
is running.
g. Debris in the hydraulic system. g. Consult factory.
h. Power unit/pump/motor failure. h. Replace power unit.
i. Platform cylinder failure.
i. Replace platform cylinder.
8. Lip extends slightly when the a. Adjustable sequence valve a. Increase the sequence valve spring
platform starts to raise. spring pressure is set too low. pressure.
9. Lip does not remain extended while a. Valve failure on power unit a. Inspect, test and replace the pilot to
the platform is lowering. endhead. close check valve if necessary.
10. Lip does not store or store properly a. The lip stop bolt is not adjusted a. Verify that the lip stop bolt is properly
in lip supports. properly. adjusted.
b. Debris. b. Remove debris from the lip supports
and hinge spools.
c. Lip supports are damaged. c. Inspect, repair or replace the lip
supports as needed.
d. ARTD actuator failure. d. Verify that the ARTD actuator is
functioning properly.
When checking for a hydraulic
system leak, first look for the wet
hoses or fittings without the power
unit running. Once the suspected
leak has been located, have an
assistant power-up the pump. MOVE
A PIECE OF CARDBOARD AROUND
THE SUSPECTED LEAK TO LOCATE
THE FAULTY PART. DO NOT USE
YOUR HAND. MAKE SURE TO KEEP
HANDS, ARMS AND FACE AWAY
FROM THE AREA OF THE
SUSPECTED LEAK. High pressure
hydraulic fluid can be an invisible
spray that will penetrate flesh.