Limitorque QX Electronic Actuator FCD LMENIM3306-06 – 07/14
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Actuator Fails to Operate from REMOTE Controls
1. Check that the actuator will operate from “LOCAL.” If not, then carry out the checks described below.
2. Check that the red knob is in “REMOTE.”
3. ESD signal may be present or absent at the terminals. Check for signal and adjust as necessary. (“ESD ACTIVE”
at display.) If actuator was previously operated in “LOCAL,” then the fault is probably in the remote control circuit.
Check the integrity of the cabling and that the connections to the terminals are in accordance with the wiring
diagram. If motor runs in “LOCAL,” but not “REMOTE,” adjust ESD to be greater than local (“ESD > LOCAL”).
4. Confirm correct monitor relay operation. See Table 3.6.
5.2.2 Jammed Valve Detected
1. Check that position limits have been set correctly. If valve is position-seated, the limits should stop the motor just
before the end-of-travel. Recalibrate the position limits if necessary. See Section 3.5.4, Setting Position Limits.
2. Check that torque settings are correct for the valve. Recalibrate if necessary. See Section 4.7, Torque Setup.
3. Check the condition of the valve and lubrication of the valve stem and thrust bearings. The valve may have
remained in the same position for a long time and become corroded internally or externally. Engage manual over-
ride and employ the handwheel drive to unseat the valve.
4. Verify that the actuator will now operate the valve. Open and close the valve a few times to check for correct opera-
tion throughout the travel. See note next page.
NOTE: To free a jammed valve from the “CLOSE” or “OPEN” position, engage manual override and attempt to unseat it
using the handwheel drive. If a rising stem valve is jammed in the close position, loosen the fixing bolts that attach
the thrust base to the valve. This will release the compression in the drive components and reduce the effort to
unjam the valve. Partly open the valve, then retighten the bolts.
5.2.3 Actuator Operates but Does Not Drive Valve
1. Verify that the declutch lever has returned to motor-operated position.
2. Verify that the stem nut is fitted correctly in the actuator base.
3. Verify that the stem nut has sufficient engagement with the valve stem.
4. Verify that the key is fitted in bore/keyway applications.
5.2.4 Valve Does Not Seat Correctly
1. Verify that position limits are calibrated correctly for the valve travel.
2. Verify that the torque-seating valves have been configured to close on torque, not position.
3. Verify that closing torque value has been set high enough to suit the process conditions.
4. Verify that the valve is not obstructed.
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