What is the most probable cause for a valve to be stuck after adjusting the packing gland?

When a valve is stuck after the packing gland has been adjusted, the most probable cause is that the operator overtightened the packing. Tightening the packing too much can compress it excessively, which leads to additional friction between the packing and the stem of the valve. This increased friction can prevent the valve from moving freely, resulting in it becoming stuck.

Effective packing adjustments require a balance; if the packing is too loose, there may be leaks, but if it is too tight, it can cause operational issues such as sticking or harder operation. This understanding is crucial for maintaining the proper functionality of valves in a high-pressure system, where smooth operation is essential for safety and efficiency. Additionally, while other issues such as wrong packing type or pipeline obstructions can cause problems, they are less directly related to the immediate effects of improperly adjusted packing, making overtightening the most probable cause in this scenario.