When a pump is running, how should the packing leak?

When a pump is running, the packing should leak only slightly, which is considered a normal and acceptable condition. This slight leakage is actually beneficial as it helps to keep the packing lubricated and cool, thereby preventing excessive wear. When the pump is in operation, some fluid must escape from the packing to maintain the right balance between sealing effectiveness and lubrication.

If the packing does not leak at all, it could indicate that the packing is too tight or improperly adjusted, potentially leading to overheating and premature failure. On the other hand, heavy leakage suggests that the packing is either worn out or needs adjustment, which could result in inefficient pump operation and loss of fluid. Lastly, if the packing only leaks when turned off, it may indicate issues with pressure relief or other mechanical problems that should be addressed. Thus, a slight leak is the optimal scenario to ensure efficiency and longevity of the pump's components.