Service Manual Damcos LPU: Troubleshooting Guide LPU
SM 8000-100-01 Ed 04 February 2017
58
Spring actuator only partly closing or not starting to close
Action: Check that throttle valve for adjustment of closing speed is not blocked.
Open bypass while motor is not operated.
Then if: • Spring actuator closes
Solenoid valve coil is still energized while valve is required to be closed!
This might be due to that valve has been opened by hand pump or filter below pressure switch is
blocked or too fast closing speed so that emergency valve has no pressure and is closing before
actuator is closed.
If this is the case then:
– repeat opening and closing command (by remote operation) for LPU.
If closing does not function check that the power for the solenoid valve is turned off.
If not check relay in control cabinet (power controlled with separately connected solenoid
valve), or on printed circuit board (P-Net).
Else remove coil from solenoid valve. Check filter below pressure switch (valve must be
closed). Adjust closing speed valve to fully closed, open it 1 revolution and check again. If the
actuator now closes closing speed can be increased step by step. If closing speed cannot be
sufficient then B-line between LPU and actuator is checked for blocks that can throttle oil flow.
• Spring actuator remains open
The fault is to be found outside the LPU.
For KFR push button for emergency operation might be blocked. Valve is sticking, or fault on
spring actuator.
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