Flowserve LHS Hydraulic Heavy-Duty Actuator Series - Manual (Page 21)

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LHS Hydraulic Heavy-Duty Actuator Series FCD LFENIM0003-00-AQ 7/14
Problem Possible Cause Solution
The actuator does not
move
Actuator has not been properly
installed.
Check that all the hydraulic connections and that all the hydraulic
components have been installed correctly, and are in accordance with the
actuator operating mode.
Check that the actuator is properly connected to the valve and that there
aren’t problems in the mounting kit.
Supply Pressure Problems.
Check that sufficient supply pressure is available at actuator inlet port. If
possible, place a gage in line and monitor the pressure level, in order to
discover unexpected pressure drops.
Problems in the control panel (if
present).
Check the correct functioning of the control panel. In particular, check all
the hydraulic and electric connections.
Check the correct level of supply voltage for solenoid valves and other
electrical/electronic components.
The valve is blocked.
Check that valve is free to rotate. If necessary disassemble the actuator
from the valve.
Exhaust port(s) obstructed.
Screw cap(s) must be disengaged. Ensure vent ports are free. If not,
clean them of any obstructions and clean the dust excluders, if present.
Problem with lubricants.
Ensure that the actuator is properly lubricated, and that there is no solid-
ified grease among sliding parts or rotating parts. If actuator lubrication
is inadequate or improper, apply a uniform lubricant layer. Follow the
instructions for cylinder maintenance (para. 4.3). Consult Flowserve for
proper oil and grease to be used.
A moving part is seized up.
Check if any moving part is blocked. If so, follow the maintenance
instructions given in the relevant paragraphs of this manual or in special
maintenance operating instructions.
Leakage of the hydraulic cylinder.
A significant oil leak may prevent the actuator from operating. Ensure
that there aren’t any leaks in the hydraulic cylinder toward the outside.
If possible, detect them using a leak finder spray. Check also that there
are not leaks across the piston. If leaks are present, follow the cylinder
maintenance instructions given in paragraph 4.3.
The actuator model is not the correct
one, or is not suitable for the plant
conditions.
Check the actuator nameplate and the plant requirements. If there are
mismatches, contact Flowserve Service Department.
Spring Problems (if actuator is a
single acting model).
Check the proper functioning of the spring can. If problems are found,
contact Flowserve Service Department.
Perform the following test: disassemble the actuator from the valve and
measure the minimum pressure values necessary to move and compress
the spring. Compare the measured values with the ones reported on the
Testing Certificate. If there are significant differences you should contact
Flowserve Service Department.
A lockout device has been inserted
and forgotten in that position.
Disconnect the lockout module.
The valve does not shut
off properly and there are
leaks
The actuator is not correctly adjusted
Adjust the end stop of the hydraulic cylinder can until the valve is leak-
tight across the seat. Follow the instructions given in the paragraph about
travel stop bolts (2.3)
The valve does not fully
perform the stroke, during
opening and closing
The actuator is not correctly adjusted
As above, check the position of the end stop in opening and closing
direction. If necessary adjust them. Follow the instructions given in
paragraph 2.3.
Exhaust port(s) obstructed
Screw cap(s) must be disengaged. Ensure vent port are free. If not, clean
them of any obstruction and clean the dust excluders, if present.
Actuator torque lower than required
In order to do a check it is necessary to perform the following test: disas-
semble the actuator from the valve and measure the minimum pressure
values necessary to move and compress the spring (if the actuator is
a single acting model) or the minimum values necessary to move the
actuator yoke and perform a stroke (for double acting models). Compare
the measured values with the ones reported on the Testing Certificate.
If there are significant differences you should contact Flowserve Service
Department.
During the stroke the
actuator exhibits excessive
amounts of backlash.
Some components are excessively
worn.
Identify and replace these components, according to the procedure
described in the relevant paragraphs of this manual, or in special
maintenance operating instructions.
In case of other problems not listed in this table, you should contact Flowserve Service Department.