You already know that maintenance is the key to keeping your valves working at their best and your facility running at its smoothest. But what type of valve maintenance program should you choose: preventative or predictive? The answer is that there’s no one right answer to this question.

This article explains the difference between preventative and predictive maintenance and gives you the tools you need to determine the best valve maintenance program to meet your needs.

What is preventative maintenance?

Preventative maintenance (also called planned maintenance) is event- or time-based. The goal is to prevent equipment from failing by performing regular maintenance.

A common example of preventative maintenance is the oil change you get for your car every 5,000 miles (event trigger) or 6 months (time trigger). Changing the oil on a regular basis keeps your car running smoothly and prevents damage to your engine. It also provides an opportunity for a technician to check your car for any small problems that might become big ones.

For valves — especially pressure relief valves — many manufacturers recommend performing preventative maintenance once a year. This not only keeps your valves working properly, but enhances the safety of your plant and saves you money by reducing downtime.

What is predictive maintenance?

Predictive maintenance (also called condition-based maintenance) is a data-driven approach, rather than an event- or time-based approach. Here, maintenance is based on the results of monitoring and testing equipment performance.

In the oil change example, rather than changing your oil every 5,000 miles or 6 months, you’d perform regular testing to monitor the condition of the engine and change the oil only when the test results showed evidence of degradation.

For control valves, diagnostic tools like ValScope allow technicians to monitor the health of a valve without removing it from service. If maintenance is required, the technician knows exactly what he needs to do. If the valve is working properly, the maintenance schedule can be extended.

Which type of valve maintenance is better?

So, which one should you use?

Both approaches have advantages for certain applications.

When to use preventative maintenance

You could take your car in for testing once a month and then, based on the data, maybe push your oil change schedule out to 8 or 9 months. But do you really want to take your car in for monthly testing? In this case, preventative maintenance is more time- and cost-effective.

For valves, the ideal maintenance program depends on several factors. For example, regularly exercising your pressure relief valves keeps them from seizing up. This is a standard part of a preventative maintenance program. Even if a valve could go another year without other maintenance, it would not be a good idea to leave it unexercised.

Also, like in the car example, there are situations in which testing valves frequently to gather predictive data isn’t as cost-effective as implementing a regular maintenance schedule.

When to use predictive maintenance

Predictive maintenance has the advantage in many situations. On a car, while preventative maintenance might not be the best choice for oil changes, it definitely would be for brakes. By monitoring your brake performance and only changing them when they’ve worn down, you can improve your safety without spending extra money replacing perfectly good brakes.

Predictive maintenance is especially useful for control valves, where there are several things that could cause a valve to malfunction — the valve itself, the actuator, the controller, and so on. Using a diagnostic tool like ValScope allows you to track performance across many factors so you can identify when and where problems are likely to occur.

Also, because the valves can be tested in situ, you don’t have to shut down your line to gather the data to make maintenance decisions.


Both preventative and predictive approaches are important aspects of an effective valve maintenance program. The best way to use these tools depends on your valves and the applications where they’re used.

Need help? Our technicians can assess your needs and recommend the best maintenance program to meet them. Contact us today.

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