What should be done when repacking valve stuffing boxes?

When repacking valve stuffing boxes, both adding oil before packing and ensuring that splits line up after packing are essential steps in the process, which makes the combination of these actions the correct choice.

Adding oil before packing helps to lubricate the packing material, which makes it easier to install and reduces the risk of damage during the packing process. Proper lubrication facilitates the packing's ability to conform to the valve stem, ensuring a tight seal without excessive friction that could lead to premature wear or failure.

Aligning the splits in the packing material is crucial for maintaining an effective sealing surface. If the splits do not line up, it can create uneven pressure on the valve stem and might allow leaks to develop. Proper alignment also helps in even wear and enhances the longevity of the packing.

Together, these practices contribute to better performance and reliability of the valve, preventing leaks and minimizing maintenance needs. Therefore, both actions need to be performed to ensure the effectiveness of the repacking process.