If a stuffing box shaft seal is leaking excessively, which action should be performed?

If a stuffing box shaft seal is leaking excessively, which action should be performed?

• A. Replace the pump
• B. Tighten the packing gland and/or replace the packing
• C. Replace bearings
• D. Increase pump speed

Answer: (B)

When a stuffing box shaft seal leaks too much, the seal isn’t being pressed firmly enough by the packing around the shaft. The packing gland applies that pressure; tightening the gland compresses the packing to improve the seal and reduce leakage. If the packing is worn or crushed, it should be replaced. Do this gradually and recheck, because over-tightening can cause excessive friction, heat, and damage. Replacing the pump or bearings won’t fix a packing leak, and increasing pump speed typically makes the leak worse by increasing pressure at the seal.

When a stuffing box shaft seal leaks too much, the seal isn’t being pressed firmly enough by the packing around the shaft. The packing gland applies that pressure; tightening the gland compresses the packing to improve the seal and reduce leakage. If the packing is worn or crushed, it should be replaced. Do this gradually and recheck, because over-tightening can cause excessive friction, heat, and damage. Replacing the pump or bearings won’t fix a packing leak, and increasing pump speed typically makes the leak worse by increasing pressure at the seal.