Why PN25 Ball Valves Need Replacement
Even though PN25 ball valves are built for durability, factors such as erosion, corrosion, mechanical wear, and seal degradation can eventually lead to performance issues. Common signs you need a replacement include:
Persistent leakage even when the valve is fully closed.
Handle resistance or stiffness during operation.
Reduced flow rate due to internal blockages or damaged ball seats.
Visible external damage like cracks, pitting, or rust.
Internal seal failure causing backflow or bypassing.
Preparation Before Replacement
Tools & Materials Required:
New PN25-rated ball valve (ensure size, end connection, and material match system requirements)
Adjustable pipe wrench or torque wrench
PTFE thread seal tape or liquid thread sealant
New flange gaskets (for flanged connections)
Safety gloves, goggles, and lockout/tagout equipment
Bucket or drain hose (for fluid removal)
Step-by-Step PN25 Ball Valve Replacement Process
1. Isolate and Depressurize the System
Close upstream and downstream valves. Fully depressurize the section where the ball valve will be replaced. In high-pressure applications, double-check with gauges before starting work.
2. Drain Residual Fluid
Remove remaining water, oil, or gas to prevent spills and ensure safety.
3. Remove the Old Ball Valve
For threaded valves: Loosen counterclockwise with a pipe wrench.
For flanged valves: Remove bolts in a crisscross pattern to prevent flange warping.
For welded valves: Cutting and re-welding by a certified welder may be required.
4. Inspect Connection Points
Clean threads, flange faces, or weld ends. Remove old sealant, rust, or gasket residue. Any debris left behind may prevent proper sealing.
5. Install the New PN25 Ball Valve
Threaded Connection: Wrap PTFE tape clockwise around male threads; tighten without overtightening to avoid cracking.
Flanged Connection: Use new gaskets; tighten bolts evenly using a torque wrench.
Welded Connection: Ensure precise alignment before welding to prevent stress points.
6. Pressure Test the Installation
Slowly repressurize the system while checking for leaks. For safety, perform a hydrostatic test if required by your industry’s standards.
Pro Maintenance Tips
Select materials wisely: Stainless steel PN25 ball valves for corrosive fluids, brass PN25 for general water and HVAC, carbon steel for industrial steam and oil lines.
Operate valves regularly to prevent seizure.
Install strainers upstream to protect the valve from debris.