How to Maintain and Troubleshoot Valves: Your Guide to Valve Maintenance
Valves are some of the most important components of industrial fluid systems, responsible for controlling and maintaining optimal levels of flow. Their reliable functionality is critically important to operational efficiency, profitability, and safety—and that means fluid system operators need a plan when it comes to maintaining and repairing their valves.
So, what do you need to know about valve maintenance and troubleshooting valves? Let’s look at some of the essentials of valve maintenance.
Good Maintenance Practices Begin with Installation
One common reason that a valve—or any fluid system component—may perform sub-optimally once in service is because it was installed improperly. A properly installed valve should help to reduce ongoing maintenance needs over the course of its life. Follow these best practices to be confident in your valve installations:
✔ Always follow the manufacturer’s installation instructions. Read the instruction manual, attend training sessions, or watch videos in order to understand the proper steps of assembly and disassembly.
✔ Be aware of the capabilities and operating parameters of the system. For example, a valve should never be placed into service where the temperature or pressure inside the system exceeds the ratings of the valve.
✔ Allow adequate space for access and future maintenance. Maintaining a valve is typically a hands-on activity. Make sure you place valves in locations that are easily accessible, when possible.
✔ Mount valves securely to a fixed location whenever possible. Use adequate supports for the tubing or piping where possible on both sides of the valve to minimize vibration.
✔ Ensure the proper orientation of the valve to allow media to flow in the correct direction
✔ Check for leaks after installation
✔ Avoid contaminants. You can do this by adding filters to your fluid system to help remove particulates that may interfere with proper valve operation. Such particles can cause damage to valve seats, contaminate your process fluid, and reduce overall flow throughout your system.
Taking these things into consideration during the installation process can help best set up your valve for reliable operation over the long term.
Performing Preventative Valve Maintenance and Troubleshooting
Once the valve has been installed, consider creating a preventative maintenance schedule in order to proactively maintain reliable operation. Preventative maintenance (PM) should help you to reduce the amount of troubleshooting you’ll need to do into the future.
But because no two fluid systems are identical, your PM schedule should be established based on the needs of your system. Consider that a number of different factors will affect the longevity of your valve’s service life, including pressure, temperature, the chemical makeup of your process fluid, and the number of on/off cycles your valve will see within a given amount of time. It’s also a good idea to check with your valve supplier for relevant PM information or advice.
Remember: Safety First!
Valve maintenance always begins with safety. Reference your company’s safety procedures before performing any valve maintenance or repair on individual valves. Certain worn or damaged components on a valve can be repaired or replaced; to identify which ones, always consult the manufacturer. When in doubt, replace the valve entirely to ensure safety.
Regardless of your parameters, the goal of any PM schedule is to periodically verify that your valves are operating properly. The most common indicator of improper operation is a leak, be it minor or significant. Leaks can be detected with your own senses—you may smell a chemical leak before you can find it visually, for instance—or with ultrasonic equipment and liquid leak detectors. Catching a valve leak can help prevent a more serious problem that could occur if the leak were to continue undetected.
Some common causes of leakage are unreliable metal-to-metal seals, contaminants in the system, improperly installed end connections, and poor tubing selection and preparation. These valve troubleshooting techniques can be deployed to help you determine your best course of action:
Test the valve. Verify its operation and determine the nature of the leak. There are two main forms of valve leakage:
- A seat leak, where the leak is contained inside the valve, but fluid passes through the seal and the valve is unable to stop the flow
- A shell leak, where fluid leaks outside of the valve into the atmosphere, often through the stem or body of the valve.
The Cost of Leaks
Leaks must be minimized as much as possible, given the potential cost, safety, productivity, and environmental implications. Consider a hydraulic fitting leaking 6 drops of fluid per minute, where each drop is .05ml. That amounts to half a liter per day, or approximately 15 liters per month, or approximately 180 liters per year. Assuming the cost of hydraulic fluid is $15 USD per gallon (or approximately $4/liter) this leak costs you over $700 USD per year in lost fluid.
Inspect the valve. Examine all internal components, including the seats, O-rings, and stem tips for wear or damage.
Repair the valve. Worn components like seats, packing, and stems can often be replaced without the need to replace the valve entirely, based on the results of your inspection. In some instances, you may need to overhaul the valve, which involves replacing all internal wear components. Check with your valve supplier for available seal kits you can use to make repairs.
Maintain the valve. Adjust your PM schedules or procedures once you gain a better understanding of how valve wear occurs in any given application. You can use tags to offer technicians quick, easy visual indicators of what individual valves do and how often they may need to be inspected.
When to Replace a Valve
Sometimes, a valve should not be repaired, but should instead be replaced with a new valve. Significant damage or other factors to critical components may require this. Some examples include:
- Heavy corrosion may deteriorate the valve body, compromising its pressure-retaining capabilities and creating a safety risk
- Major contamination that cannot be cleaned
- Overtightening a valve at its end connections can cause damage, rendering it unusable for reinstallation
There are other factors that may require replacement that have nothing to do with damage. You may determine that the cost of a new valve, combined with the labor and testing involved in repairing an existing one, is more advantageous. Potential production downtime is important to consider in any maintenance activity.
Reliable valve operation is critical to the overall health and safety of your fluid systems. Being more familiar with the proper installation of valves, knowing how to troubleshoot valves, and being able to properly implement adequate PM plans for your valves can all contribute to safer, more efficient, and more profitable operation.
Interested in learning more about valve maintenance? Swagelok offers valve training courses to help you deepen your knowledge on valves, their operation, and how to identify and solve common issues. Find out how these courses could benefit your operation.