Hydraulic System Troubleshooting; Mechanical Troubleshooting - Chamberlain LiftMaster Professional HS670 User Manual

HYDRAULIC SYSTEM TROUBLESHOOTING

SYMPTOM
UNIT SOUNDS LIKE IT IS
WORKING BUT WHEELS
DO NOT TURN
RUNS BACKWARDS
RUNS SLOW
JERKING MOTION
WILL NOT OPEN
FLUID LEAKS

MECHANICAL TROUBLESHOOTING

SYMPTOM
UNIT SOUNDS LIKE IT IS
WORKING BUT GATE
DOES NOT MOVE
JERKING GATE MOVEMENT
SQUEALING SOUND WHEN
GATE MOVES
GATE WILL NOT STOP IN
ONE DIRECTION
DAMAGED DRIVE RAIL
EXCESSIVE WHEEL WEAR
T R O U B L E S H O O T I N G
POSSIBLE CAUSES
A, B, F, H or I
D or C
A, B or I
B
C
D, E or G
POSSIBLE CAUSES
A, C or G
A, C, D, F or G
B, E or G
H
B, D, F or G
C, F, G, I or A
27
(A) BYPASS VALVE:
It MUST be in the "automatic" position (horizontal). If it is in
the manual position, no fluid gets to the drive motors, so
they won't turn. If the bypass lever is between positions,
fluid will be bled off, so motors will turn slower.
(B) PUMP:
Air may be in the system, allow about 15 seconds for air to
dissipate. Filter may be clogged. Check fluid level.
(C) DIRECTION VALVE:
Press and hold the manual override button on valve. If unit
works okay, check valve for proper wiring. See page 31.
(D) HOSES:
Double-check hose routings between pump and motors. If
wrong, fluid will flow in the wrong direction. Check for leaks
and/or pin holes.
(E) FITTINGS:
Tighten if required. See page 29.
(F) CHECK VALVE: See page 29.
(G) SEALS:
(H) RELIEF VALVE: See page 29.
(I) FLUID: Check fluid level in tank.
(J) THREE PHASE MOTOR MISWIRED
See page 26, "Motor runs but gate does not move."
(A) DRIVE WHEELS:
Are the drive wheels slipping? Check the spring tension.
Are the drive wheels wearing excessively? Check the spring
tension.
Make sure that the key and bolt holding the drive wheels on
are secured.
(B) GUIDE WHEEL:
Check for wheel mis-alignment.
Check guide wheel assembly for interference with drive rail.
(C) DRIVE RAIL:
Check for damage, severe bending or misalignment.
If drive rails were spliced together, check for improper
splicing or damaged splices.
(D) PIVOT ARMS:
Make sure that both, upper and lower pivot arms move freely.
(E) SEPARATOR BOLT:
Make sure it's not interfering with the drive rail.
(F) OPERATOR MOUNTING:
Make sure operator is fastened to pad securely. Check for
operator misalignment.
(G) GATE:
Check the gate and its hardware for damage and/or bad
rollers.
(H) LIMIT SWITCHES:
Has a lever on one of the limit switches moved or broken.
Verify the presence of limit shoes.
(I) SPRINGS:
Check for proper spring tension.