At BI-TORQ, we supply industry-leading valve automation products, including pneumatic and electric actuators. Our pneumatic actuator offerings include double-acting and spring-return rack and pinion models, while our electric actuator offerings include 100–20,000 inch-pound capacity variants.
With almost 40 years of experience in the valve automation industry, we’ve taken note that even the best components can experience problems after years of use. If you’re experiencing diminishing performance from your actuator (or abrupt disturbances in consistency), the following guide can help you in troubleshooting the problem.
What is Wrong With My Valve Actuator?
Troubleshooting your valve actuator might seem daunting, but it doesn’t have to be. The problem can quickly be narrowed down by ruling out a few easy items.
Is the valve impeding actuator movement due to binding or an obstruction? An easy way to check this is to take the actuator and any mounting so that the valve stem can be directly accessed. If the valve is small enough can it be fluidly operated from the open or closed position? Can flow be checked downstream?
If the valve is in good working order, you can check the mounting to see if anything is binding or limiting the transmission of toque from the actuator to valve.
If the above items are not the problem and can be ruled out, then it is time to check the actuator.
Pneumatic valve actuators are among the easiest actuators to diagnose. Depending on their valve opening/closing mechanism, they fall under one of two categories: double-acting or spring-return. When troubleshooting, it’s important to confirm the type of actuator you have as problems may vary between the two.
The first thing to check is for supply problems – is the actuator getting the minimum air supply pressure as required in the manual? Causes of supply problems can be a leaky hose, compressor problems, pressure drop, or obstructed/compromised hose.
The next items to check is the actuator seals. The potential causes for leaks are the same whether the valve is double-acting or spring-return. Inspect the seals carefully, listening for any leaks or use soap and water to look for air bubbles from a leak. If leak is found anywhere, it is best to order a seal kit and replace all the actuator seals at once.
For issues with pneumatic actuator that have accessories, troubleshooting is slightly more complicated. To identify the problem:
- Check the NAMUR solenoid seal is good.
- Check the positioner for a good fit and allows for a smooth input.
- Check the electrical components: ensure that enough power is being applied, that the coil voltages are appropriate, and that control signals are good and stable.
Typically, these steps are enough to troubleshoot a rack and pinion actuator and can remedy most of the cases that may happen.
Compared to pneumatic actuators, electric actuators are more difficult to troubleshoot.
If an electric valve won’t open or close at all, there are several likely causes. To verify which is causing the issue:
- Check the actuator power voltage, control voltage, and supply amperage to ensure that they are within normal limits.
- If those measurements are all normal, check for a blown fuse, capacitor, or power board failure.
- Assess the open and close limit switches and cams. This can be a big cause of an actuator not open and closing a valve properly.
- If there are no electrical issues, move on to assessing mechanical functioning. This inspection includes checking for sticking or binding and examining the wires to ensure that they haven’t come loose.
Components of Actuators to Check
As outlined above, there are several causes of valve malfunctions and underperformance. However, the majority of these causes are related to one of five components, including:
- The valve. Most of the time, actuator problems aren’t caused by the actuator at all. Service experts indicate that approximately 70% of actuator issues result from problems with the valve, such as a worn valve stem, excessive torque, or obstructions.
- The drive. The drive is on the bottom of the actuator and outputs the torque to the valve shaft directly or via a mounting coupler. If the drive gets worn, the valve stem won’t move properly.
- The motor. In electric actuators, the motor provides the torque necessary to open and close the valve. When the motor fails, the actuator will not function.
- Open and close switches/cams. This component is specific to electric actuators. It initiates the opening and closing operation in the actuator. If it fails, the actuator stops working.
Contact BI-TORQ Today
There are several common causes of valve actuator malfunctioning and underperformance. Determining which one is causing your issue, is the key to resolution.
If you find yourself struggling to diagnose a failing actuator, BI-TORQ can help. As a full-service provider of valve automation solutions, we can answer all of your questions and provide high-quality replacement components where necessary. We also offer high-performance pneumatic and electric actuators, should you need a more comprehensive refit.