Motor Operated Valves (MOVs) are very important parts of industrial pipelines because they control the flow of fluids in a variety of industries, including oil and gas, water treatment, and power generation. MOVs are very important for making sure that operations run efficiently and safely. They do this by acting as isolation valves at important locations in fluid supply lines.
Despite their importance, MOVs are susceptible to malfunctions, which can interrupt industrial processes and lead to downtime. Troubleshooting these issues promptly is essential to minimize disruptions and maintain productivity.
n this article, we explore typical issues with motor-operated valves and provide brief troubleshooting steps to efficiently resolve them. By understanding the root causes of these issues and implementing appropriate solutions, industries can enhance the reliability and performance of their MOV systems, thus optimizing operational outcomes.
Problem No.1: Actuator Motor Not Starting
Possible Reasons
Solutions
Lack of power supply
Ensure the actuator is connected to a power supply.
Broken electric wires or loose wiring terminals
Inspect and repair any damaged wires or terminals.
Incorrect or insufficient supply voltage
Verify the voltage meets requirements as per the instrument data sheet.
Overheat protector activated due to high ambient temperature or valve obstruction
Check and Replace the capacitance component if needed.
Limit switch problem.
Check and adjust limit switches per instruction.
Cam assembly problem.
Check and adjust cams per instruction.
Integrated circuit breaker tripped.
Turn off the unit’s power for 20 seconds, then turn it back on.
Dead or open short in control harness.
Check harness for cuts in insulation or sharp pinch point. Conduct a continuity check on each of the wires contained within the harness. Check connectors for damage or corrosion. Repair or replace as needed.
An actuator control circuit that has a dead or open .
Check actuator housing for damage or missing hardware. Check actuator for internal corrosion. Check for loose motor lead. Use compressed air and electrical contact cleaner to clean the circuit. Solder connections if necessary. Replace circuit board assembly if required.
Failed gearmotor.
Disconnect motor leads at circuit board or motor. Apply power directly to motor terminals. Motor should run continuously when power is applied. Motor should be replaced if the rotation is not smooth.
Problem No.2: Actuator Motor Running Continuously
Possible Reasons
Solutions
Limit switch problem.
Check and adjust limit switches as per instruction provided in the MOV manual
Cam assembly problem.
Check and adjust cams as per instruction provided in the MOV manual
Defective or damaged circuit board component.
Replace circuit board assembly.
Problem No.3: Opening & Closing Indicator Light Doesn’t Glowing
Possible Reasons
Solutions
The indicator light may be physically damaged or burnt out.
Replace the indicator light with a new one to restore indication.
Malfunctioning limit switches can disrupt the indicator light.
Replace the malfunctioning limit switch with a good one and also ensure proper electrical connection.
Misalignment or mechanical obstruction in the adjustment mechanism may disrupt indicator light operation.
Inspect the adjustment mechanism for any blockages or misalignments, and perform necessary adjustments to restore proper function with instrument data sheet ot manufacturer instruction manual
Problem No 4: Constantly Tripping Integrated Circuit Breaker or Blowing of Line Fuse
Possible Reasons
Solutions
Valve operating torque excessive; tight from incompatible valve or media, or buildup.
Remove motorized actuator from valve. When possible, manually turn the valve with a torque wrench. Verify the actuator can handle the valve torque. Refer to Actuator Information chart in Engineering section of catalog. Disassemble and clean valve.
Defective or damaged circuit board component.
Many MOV have internal relays. Observe for audible click upon activation. Bypass circuit board assembly to test motor, Replace circuit board assembly if needed.
Failed gearmotor.
Failed gearmotor. Replace circuit board assembly if needed. At the circuit board or motor, disconnect the motor leads. Apply power directly to motor terminals. Motor should run continuously when power is applied. Motor should be replaced if the rotation is not smooth.
Problem No.5: Opening Position Change Constantly
Possible Reasons
Solutions
Source of signal has interferences
Check the input signal for any external interference and eliminate sources of signal disruption.
potentiometer generated interference
Replace the potentiometer if it is generating interference, causing erratic behavior in the valve’s opening.
Voltage divider gear or opening gear loose
Tighten up the screws of the voltage divider gear or opening gear to ensure stability in the mechanism.
Problem No.6: Valve Fails to Open
Possible Reasons
Solutions
Incorrect actuator voltage supply or non-compliance with valve specifications.
Verify actuator voltage matches requirements as per valve specification with multimeter.
Inadequate supply amperage, particularly for low voltages (12/24vDC).
Check supply amperage to ensure it meets specified criteria, especially for lower voltage settings. Ensure sufficient power supply for effective valve operation.
Improper functioning of the actuator
Engage manual override on the actuator to determine if the valve can be opened manually. Confirm proper functioning of the actuator in manual mode.
valve misalignment
Inspect valve body to verify alignment with flanges. If necessary, remove the actuator and utilize a spanner on the valve to detect any binding or obstruction in valve body
Problem No.7: Valve Fails to Close
Possible Reasons
Solutions
Incorrect actuator voltage supply
Verify actuator voltage matches requirements specified in the instruction manual
Inadequate supply amperage, particularly for low voltages (12/24vDC).
Ensure sufficient power supply for effective valve operation.
Improper functioning of the actuator
Engage manual override on the actuator to determine if the valve can be closed manually and also Confirm proper functioning of the actuator in manual mode.
Valve misalignment
Inspect valve body to verify alignment with flanges. If necessary, remove the actuator and utilize a spanner on the valve to detect any binding or obstruction.
Problem No.8: Valve Stem Leakage and Seat Passing
Possible Reasons
Solutions
Accumulation of debris or contaminants on valve seat.
Strip and clean valve seat thoroughly to remove any debris or contaminants. Re-test the valve to ensure leakage is resolved.
Seats damaged or worn out.
Repair the valve body with repair kit.
The valve is not closing to the correct position.
Adjust limit switches of actuator as per manufacturer instruction
Loose body bolts or excessive operating pressure.
Check bolts and confirm application is within recommended pressure ratings
Defective body seals.
Repair the valve body seat with repair seal kit.
Problem No.9: Electrical Issues
Possible Reasons
Solutions
Power outage or fluctuations, Disconnection or faulty connection to power source
Verify power source for stability and reliability. Install backup power or surge protection devices if necessary
Frayed or damaged wires or Loose connections
Inspect wiring for signs of damage or wear. Tighten loose connections. Replace damaged wiring as needed
Motor Failures
Check motor for signs of overheating or abnormal noise. Replace faulty motors with new ones as necessary
Damaged Electrical Components like Burned-out capacitors and Faulty limit switches
Inspect electrical components for signs of damage, Replace damaged components with new ones as required
Problem No.10: Mechanical Issues
Possible Reasons
Solutions
Continuous usage leading to deterioration of moving parts
Regular maintenance and lubrication to reduce wear. Replace worn components as part of preventive maintenance.
Exposure to corrosive fluids or environments
Apply protective coatings or materials to susceptible parts. Replace corroded components as necessary.
Improper installation or handling, causing components to be out of alignment
Realign components according to manufacturer’s specifications. Ensure proper installation procedures are followed
Impact from external forces, accidents, or improper handling
Inspect components for damage and replace as needed. Handle components with care to prevent further damage.
Problem No.11: Control System Issue
Possible Reasons
Solutions
Improper configuration of control settings or parameters
Verify and adjust control system settings as per manufacturer’s recommendations. Ensure proper MOV configuration steps are followed.
Incorrect programming of control parameters
Review and correct programming errors in the control system. Ensure MOV parameters are set according to specifications
Errors in the control system software
Update software to the latest version available. Contact MOV manufacturer for patches or fixes for identified bugs
Problem No.12: Communication Issue
Possible Reasons
Solutions
Network outages or disruptions. Interference from other electronic devices or equipment
Investigate and resolve network issues promptly. Shield communication equipment from interference sources.
Malfunctioning transmitters, receivers or communication modules.
Test communication devices for functionality. Replace or repair faulty MOV components as necessary.
Incorrectly configured communication settings or parameters.
Review and adjust communication settings as per MOV manufacturer’s guidelines. Ensure proper configuration steps.
Problem No.13: Valve Operating Torque Excessive
Possible Reasons
Solutions
Swollen seals or particulate buildup in valve chamber.
Check valve body for compatibility with product. May require valve cleaning, repair kit, or new valve.
Valve bolts too tight
Loosen bolts slightly.
Stem nut too tight or damaged stem seal.
Loosen stem nut slightly. Repair the valve seals with seal kit.
Problem No.14: Excessive Noise or Vibrations During Operation
Possible Reasons
Solutions
Misalignment of valve components or actuator
Inspect valve assembly for proper alignment of components. Realign as necessary according to manufacturer’s specifications.
Worn or damaged bearings in motor or gearbox
Check motor and gearbox for signs of wear or damage. Replace bearings if necessary.
Loose mounting or fastening of valve or actuator
Tighten mounting bolts and fasteners securely to eliminate any looseness.
Fluid flow-induced vibrations
Analyze fluid flow conditions and consider installing vibration dampening measures such as vibration isolators or dampeners.
Internal components rubbing or interfering with each other
Inspect internal components of the valve and actuator for signs of rubbing or interference. Adjust or replace components as needed to prevent contact.
Problem No.15: Slow or Delayed Response of Valve to Control Signals
Possible Reasons
Solutions
Inadequate power supply or voltage fluctuations
Ensure stable and sufficient power supply to the valve actuator. Address any voltage fluctuations or electrical issues in the power source.
Faulty control signal transmission
Check the integrity of control signal transmission lines and connections. Repair or replace any wires or connectors that have been damaged.
Improperly calibrated control system
Calibrate the control system according to manufacturer’s specifications. Verify that control parameters are set correctly for desired response times.
Mechanical obstructions or binding in valve assembly
Inspect valve assembly for any mechanical obstructions or binding that could impede movement. Clear obstructions and lubricate moving parts as necessary.
Degraded performance of actuator components
Check for worn or damaged actuator components such as gears, bearings, or seals. Replace any degraded components to restore proper functionality.
Problem No.16: Inconsistent Valve Positioning or Drifting
Possible Reasons
Solutions
Inaccurate feedback signals from position sensors
Calibrate position sensors or replace faulty sensors to ensure accurate feedback signals.
Loose connections or wiring issues in control circuitry
Inspect control circuitry for loose connections or damaged wiring. Tighten connections and repair or replace wiring as needed.
Mechanical wear or backlash in valve linkage
Inspect valve linkage for signs of wear or excessive backlash. Adjust or replace worn components to eliminate play and ensure precise positioning.
Interference from external environmental factors
Shield valve and control system from external factors such as electromagnetic interference or temperature fluctuations. Implement protective measures as needed.
Improperly configured control loop parameters
Review and adjust control loop parameters to optimize valve positioning performance. Consult manufacturer documentation for recommended settings.
Problem No.17: Valve Sticking or Binding During Operation
Possible Reasons
Solutions
Buildup of debris or contaminants in valve assembly
Clean valve assembly thoroughly to remove any debris or contaminants. Inspect and clean internal components such as seals and bearings.
Insufficient lubrication of valve components
Apply appropriate lubricants to moving parts of the valve assembly to reduce friction and prevent sticking.
Corrosion or deterioration of valve materials
Inspect valve materials for signs of corrosion or deterioration. Replace corroded or degraded components with new ones.
Misalignment or improper seating of valve components
Inspect valve components for proper alignment and seating. Realign or adjust components as necessary to ensure smooth operation.
Excessive operating pressures or temperatures
Monitor operating conditions and ensure they remain within design limits. Implement pressure or temperature control measures if necessary to prevent damage to the valve.
Problem No.18: Inaccurate Valve Positioning or Control
Possible Reasons
Solutions
Faulty position feedback sensor
Inspect and calibrate position feedback sensors. Replace sensors if malfunctioning.
Incorrect calibration of control system
Recalibrate control system according to manufacturer’s specifications. Ensure accurate control parameters.
Mechanical wear or slack in valve linkage
Inspect valve linkage for wear or slack. Adjust or replace worn components to eliminate play and improve control.
Interference from external sources
Shield valve and control system from external factors like electromagnetic interference or vibrations.
Improperly sized or mismatched actuator for the valve
Ensure actuator is correctly sized and matched to the valve. Replace or upgrade actuator if necessary for accuracy.
Problem No.19: Excessive Heat Generation in Actuator
Possible Reasons
Solutions
Overloading or excessive torque demand on actuator
Reduce torque demand by adjusting valve parameters. Ensure actuator is appropriately sized for the application.
Poor ventilation or airflow around actuator
Improve ventilation by removing obstructions and ensuring adequate airflow. Consider additional cooling mechanisms.
Faulty internal components or wiring in actuator
Inspect internal components and wiring for damage or malfunction. Replace damaged components and repair faulty wiring.
Excessive ambient temperature
Reduce ambient temperature by providing shade or insulation. Consider relocating actuator to cooler environment.
Inadequate lubrication of moving parts
Ensure all moving parts are properly lubricated. Regularly inspect and lubricate components as part of preventive maintenance.
Initial Troubleshooting Steps for Motor Operated Valve (MOV) Issues
When encountering problems with motor operated valves (MOVs), a systematic approach is essential to diagnose and resolve issues effectively. Below are detailed steps to troubleshoot MOV problems:
Step
Description
Action
1.
Check MOV Display
Examine the MOV display to determine its power status and indication presence. Look for Open or Close Feedback when power is lost, and verify text message display when power is ON.
2.
Check Power Supply
Ensure that the power supply to the MOV is functional. Verify the electrical power source and check the MOV’s 9-volt battery functionality if power is lost.
3.
Verify Electrical Isolation
Determine whether the MOV is electrically isolated or not. Investigate if the MOV is electrically isolated and check the incoming power if it’s not isolated.
4.
Check Indicator Light
Inspect the indicator light to see if it’s functioning properly. Replace the indicator light if it’s malfunctioning.
5.
Verify Backlight
Confirm if the display backlight is ON when electrical power is present. Ensure that the backlight is ON for power indication.
6.
Check Interlock Inhibition
Identify any interlock that may be inhibiting the operation of the MOV. Replace the interlock if necessary to ensure smooth operation.
7.
Verify MOV Mode
Physically inspect the MOV to determine its mode of operation. Put the MOV in Remote mode if necessary using the push buttons provided.
8.
Check Digital Communication
Confirm the device address and Baud Rate for digital communication. Review the communication settings and configurations to ensure proper communication.
9.
Verify Cable Connections
Inspect the cable connections in the MOV and the system marshalling cabinet. Ensure that the MOV is receiving commands from the system when in Remote mode.
10.
Set MOV Feedback
Adjust the feedback through the Setting Tool or local buttons on the MOV. Check the relay status and configuration for feedback, and replace faulty relays or wiring if necessary.
11.
Recheck the MOV Torque Value
Ensure that the torque value is within specified limits. Consult the Mechanical team before adjusting the torque, and avoid increasing it without proper consultation.
12.
Investigate Motor and Gearbox of MOV
Check the engagement of the Motor and Gearbox, as well as the MOV encoder for position feedback. Verify that the Motor and Gearbox are properly engaged and aligned.
13.
Operate MOV Locally
Attempt to operate the MOV locally through the handwheel or Setting Tool. Investigate further if issues persist, and drop the MOV for valve body inspection if necessary.
14.
Allow MOV to Cool Down
If the Thermostat Alarm is triggered, allow the MOV to cool down. Inspect the temperature sensing element inside the MOV actuator casing if the alarm persists after cooldown.
With over 24 years of dedicated experience, I am a seasoned professional specializing in the commissioning, maintenance, and installation of Electrical, Instrumentation and Control systems. My expertise extends across a spectrum of industries, including Power stations, Oil and Gas, Aluminium, Utilities, Steel and Continuous process industries. Tweet me @sundareshinfohe
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