{"id":3567,"date":"2026-10-10T13:28:21","date_gmt":"2026-10-10T05:28:21","guid":{"rendered":"http:\/\/www.goldenbatteries.com\/blog\/?p=3567"},"modified":"2026-10-10T13:28:21","modified_gmt":"2026-10-10T05:28:21","slug":"what-maintenance-is-required-for-trunnion-mounted-ball-valves-45eb-5f01f5","status":"publish","type":"post","link":"http:\/\/www.goldenbatteries.com\/blog\/2026\/10\/10\/what-maintenance-is-required-for-trunnion-mounted-ball-valves-45eb-5f01f5\/","title":{"rendered":"What maintenance is required for trunnion mounted ball valves?"},"content":{"rendered":"

If you\u2019ve ever relied on trunnion mounted ball valves to keep your oil and gas, chemical processing, power generation, or water treatment lines running without a hitch, you know these components are the unsung heroes of industrial piping. Unlike their floating ball counterparts, trunnion valves are designed with axial support for the ball, which lets them handle higher pressures, larger flow rates, and more extreme operating conditions\u2014all without warping or leaking. But here\u2019s the thing: even the most robust trunnion ball valves won\u2019t perform at their best if you skip regular maintenance. As a supplier that\u2019s worked with operators across heavy industry for over a decade, I\u2019ve seen firsthand how small, consistent upkeep can extend a valve\u2019s lifespan by years, while cutting unplanned downtime and emergency repair costs. Today, I\u2019m breaking down exactly what maintenance your trunnion valves need, when to do it, and why it matters for your bottom line. Trunnion Mounted Ball Valves<\/a><\/p>\n

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First, let\u2019s get clear on one thing: trunnion ball valve maintenance isn\u2019t a one-size-fits-all task. The needs of a valve in a high-pressure hydrogen service plant are very different from one in a municipal water treatment facility, and a valve in a cold-weather refinery will face far different stresses than one in a desert desalination plant. But regardless of your application, there are core maintenance steps that apply to every trunnion mounted ball valve, paired with checks tailored to your operating environment. I always tell clients to think of trunnion valve maintenance in two buckets: routine, scheduled tasks you can do without shutting down your full line, and more thorough, periodic inspections that require partial or full line isolation.<\/p>\n

Starting with the routine daily and weekly checks\u2014these are the quick, low-labor steps that catch issues before they turn into failures. The first thing you should do every time you walk by a valve: run a visual inspection of the actuator and valve body. Look for any signs of seepage around the stem or valve body joints. A tiny dribble of fluid that goes unnoticed can corrode the stem threads or seat surfaces over time, leading to full leakage later. For manually operated valves, check the handwheel or lever for signs of sticking when you open or close the valve. If it feels stiff, that\u2019s a warning that the stem isn\u2019t moving smoothly, which can strain the valve\u2019s internal components. For actuator-driven valves (pneumatic, electric, or hydraulic), listen for unusual clicking or grinding during cycling\u2014those noises usually mean the actuator isn\u2019t aligned properly or the stem is catching on debris.<\/p>\n

Once a month, I recommend pulling a bit more data on each valve\u2019s performance. Log the number of times it cycles (opening and closing) and compare it to the baseline number when the valve was first installed. If it\u2019s cycling more often than expected, that could mean there\u2019s a leak upstream or downstream that\u2019s forcing the valve to compensate, or the internal seals are wearing out and causing pressure buildup. For valves in hazardous fluid service, check the air supply to pneumatic actuators, or the power connections for electric actuators, to make sure they\u2019re running at the correct pressure or voltage. Even a 10% drop in pneumatic pressure can make a valve only partially open or close, which will cause erosion of the ball and seat surfaces over time.<\/p>\n

Now, moving to the more involved periodic maintenance\u2014these tasks are usually done every six months to two years, depending on your operating conditions, and require isolating the valve, draining the line, and accessing the internal components. The most critical part of a trunnion valve is its seat and ball assembly, because that\u2019s what creates the seal that prevents leakage. Unlike floating ball valves, trunnion valves use spring-loaded seats that press against the ball, so regular lubrication and seat inspections are non-negotiable.<\/p>\n

Lubrication is a big one, and I can\u2019t tell you how many operators either over-lubricate or under-lubricate their trunnion valves. Over-lubrication can cause built-up grime to get trapped between the ball and seats, leading to sticking and wear. Under-lubrication, though, means the seats and stem can\u2019t move smoothly, leading to increased friction and pressure on the trunnion bearings. The right approach: use the lubricant recommended by your valve manufacturer (not just any generic industrial grease). For most trunnion valves, we supply a food-grade, high-pressure synthetic lubricant that works in temperatures from -40\u00b0F to 350\u00b0F, and it\u2019s designed to not react with the process fluids common in oil and gas and chemical processing. Every six months, inject a small amount of lubricant through the grease fitting on the valve\u2014usually just 10 to 15 grams, depending on the valve size. If you notice old, dirty grease coming out of the vent fitting while you inject, that\u2019s a sign you need to clean the fitting and lines before adding fresh lubricant, to avoid pushing contaminants into the valve body.<\/p>\n

When you do open a valve for periodic inspection, the first thing to check is the ball and seat surfaces for signs of wear, corrosion, or scoring. Scoring is a common issue in valves handling abrasive fluids like sand-laden crude oil or mineral slurries\u2014small scratches on the ball or seat can create gaps that lead to leakage. If the scratches are deeper than 0.5mm, you\u2019ll need to replace the seats; smaller scratches can usually be polished out with a non-abrasive compound, as long as you don\u2019t damage the ball\u2019s precision surface (the ball on a trunnion valve is machined to within microns of perfect roundness, so even a tiny nick can ruin the seal). Also, check the trunnion bearings\u2014these are the small, heavy-duty bearings that support the ball from below and above, taking the full weight of the process pressure. If you hear grinding or feel play when you rotate the ball by hand, the bearings are worn and need to be replaced.<\/p>\n

Another key internal check is the valve\u2019s body and bonnet for corrosion. Even in mild applications, valves can develop pitting over time from moisture or process chemicals. If you notice any deep pits on the valve body walls, that\u2019s a sign the valve is at risk of failure, especially in high-pressure service. If the pits are minor, you can have the valve reconditioned, but if they\u2019re deep enough to weaken the body, you\u2019ll need to replace it. I always advise clients to keep a spare set of seats and trunnion bearings on hand for each valve in critical service\u2014waiting three days for a replacement seat can cost tens of thousands of dollars in lost production.<\/p>\n

There are also environment-specific maintenance steps that you can\u2019t skip, depending on where your valve is operating. For valves in cold climates (temperatures below 32\u00b0F), make sure to insulate the valve body and actuator to prevent process fluids from freezing. Frozen fluids can expand and crack the valve body, or jam the ball so it breaks when you try to open it. I\u2019ve had a client in northern Canada lose a full refinery line because a valve\u2019s stem froze solid, and they tried to force it open, snapping the stem and causing a major leak\u2014all because they skipped insulating the valve in winter. For valves in hot, humid environments (like coastal refineries), you\u2019ll need to inspect the valve\u2019s external coating every three months for signs of peeling or corrosion, and reapply coating as needed to prevent rust from eating through the body. For valves handling abrasive fluids, you can increase the frequency of seat inspections to every three months, since the abrasive particles will wear down the seats much faster than in clean water or gas service.<\/p>\n

One common mistake I see many operators make is waiting until the valve is leaking to do maintenance. By the time you see a leak around the stem or body, the seats have already worn down enough that the ball is damaged, and the trunnion bearings may be on their last legs. Instead, use the valve\u2019s cycling data and pressure readings to catch issues early. For example, if you notice that the differential pressure across the valve increases when it\u2019s closed, that\u2019s a sign the seat seal is leaking, so you can schedule maintenance during a planned shutdown, rather than an emergency repair.<\/p>\n

Let me also talk about testing after maintenance, because it\u2019s just as important as the maintenance itself. Once you\u2019ve completed any routine or periodic work, you need to test the valve to make sure it\u2019s working correctly. The first test is a visual and pressure test: pressurize the valve on both sides (or isolate one side) and check for seepage around the stem and body. If there\u2019s no seepage, you\u2019re good. The second test is a cycling test: open and close the valve 10 times, checking that it moves smoothly, and that the actuator reaches full open and full close position without sticking. For valves in hazardous service, you may also want to do a leak test with a tracer gas, to catch any tiny leaks that aren\u2019t visible to the naked eye.<\/p>\n

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At the end of the day, trunnion mounted ball valves are designed for long life, but only if you treat them with consistent, targeted maintenance. As a supplier, I\u2019ve seen clients that follow a strict maintenance schedule cut their valve-related downtime by 70%, compared to those that only do maintenance when something breaks. This isn\u2019t about overcomplicating your operations\u2014it\u2019s about small, regular steps that keep your most critical components running smoothly. If you\u2019re unsure about the specific maintenance schedule for your trunnion valves, or you need help inspecting your existing valves to identify potential issues, I\u2019m here to help. Whether you need replacement parts, on-site inspection services, or advice tailored to your specific application, you can reach out to our team to discuss your needs. Don\u2019t wait until a valve fails to protect your operations\u2014start a maintenance plan today to keep your lines running reliably for years to come.<\/p>\n

Actuator<\/a> REFERENCES<\/p>\n

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  1. Hydraulic Institute. (2020). Pump and Valve Maintenance Handbook: Trunnion Mounted Ball Valves. Hydraulic Institute Press.<\/li>\n
  2. American Petroleum Institute. (2019). API 6D: Specification for Pipeline Valves. 2nd Edition.<\/li>\n
  3. Ball Valve Manufacturers Association. (2021). Best Practices for Trunnion Ball Valve Maintenance. BVMA Technical Report Series.<\/li>\n
  4. International Society of Automation. (2020). Field Maintenance Guidelines for Industrial Valves, Part 2: Trunnion Mounted Designs. ISA-75.01.05.<\/li>\n
  5. Materials Performance and Corrosion Center. (2022). Corrosion Mitigation Strategies for Trunnion Ball Valves in Harsh Process Environments. MPCC Technical Bulletin.<\/li>\n<\/ol>\n
    \n

    Wuxi PYNOS Flow-tech Co., Ltd.<\/a>
    As one of the leading trunnion mounted ball valves manufacturers and suppliers in China, we offer a wide range of products with superior quality. We warmly welcome you to buy high quality trunnion mounted ball valves made in China here from our factory. We also accept customized orders.
    Address: Sales Center: 7th Floor, No.19 Qingyuan RD, Wuxi City, Jiangsu Prov., China
    E-mail: Info@pynosvalve.com
    WebSite:     https:\/\/www.pynosvalves.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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