Repair of threaded ball valve

Operation

Operating the valve with an intermediate position of the ball is not allowed. The valve must be either fully open or fully closed.

The use of additional levers that extend the handle for opening/closing the valve is not allowed.

To avoid the ball sticking during operation, it is recommended to periodically open/close the valve.

To prevent hydraulic shocks, the opening/closing of the ball valve should be done slowly.

When there is a risk of the system freezing after draining, the ball valve should be opened/closed several times. The formation of ice in the ball valve is not allowed. If the ball valve was in a closed position during draining, water may remain in the flowing part of the ball, which, when frozen, can rupture the housing.

The pressure and temperature at the installation location of the ball valve should not exceed the working pressure. For most valve designs, operation with simultaneous maximum temperature and nominal pressure is not allowed.

It is recommended to clean the ball valve from dust and corrosion every six months, and if necessary, tighten the threaded connections.

Repair

Malfunction	Cause	Remedy
Non-hermetic sealing	Damaged sealing of the ball	Damage to the sealing may be caused by a ball with a layer of calcium deposits or a working environment containing solid inclusions. Disassemble the valve and replace the ball seals.
-	Abrasive wear of the ball. The valve was in a semi-open position, which is not allowed.	Possible if solid particles are present in the working environment that can damage the polished surface of the ball. Replace the ball or the entire valve. To prevent further damage, install a mesh filter in front of the valve.
Leakage along the valve stem	Damaged stem seal ring	Drain the pipeline, remove the flywheel, unscrew the tightening nut of the seal, remove the retaining ring holding the seal and the seal itself. Install a new seal, retaining ring, nut, and flywheel.
Unable to open/close	The ball is stuck	Replace the ball. See disassembly instructions below.

Disassembly Procedure for Brass Threaded Ball Valve

To perform maintenance on a ball valve, the area where it is installed must be emptied, and the valve must be removed.

Remove the flywheel and unscrew the nut holding the stem seal. Remove the retaining ring, stem seal, and stem itself.

The brass ball valve body is glued with sealant, so some manufacturers recommend heating the joint up to 200°C before disassembly.

Screw the threads into the valve sockets and secure one side of the body in a vise, while rotating the other side with a wrench. Remove the stem seal and ball.

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