Valve packing leakage reasons: 1. Packing gland is not compressed 2. Packing due to the use of too long or improper failure to failure Failure to eliminate: 1. Tighten the nut evenly, the packing pressed 2. Replace the packing seal surface seepage Leakage reasons: 1. Sealing surface contaminants attached 2. Sealing surface damage failure to eliminate: 1. The contaminants removed 2. Rework finishing or replacement valve body and valve cover leakage at the junction: 1. Connection Uneven bolt fastening 2. Flange sealing surface damage 3. Gasket rupture or failure Failure to eliminate: 1. Uniform tightening 2. Reshaping 3. Replace the new gasket Hand wheel rotation is not flexible or the flap can not be opened and closed Reason: 1. The packing is pressed too tightly 2. The packing plate and crook are skewed 3. The valve stem nut is damaged 4. The thread of the valve stem nut is severely worn or broken 5. The stem bending fault elimination method: 1. Loosen the packing plate On the nut 2. Correction packing plate 3. Disassemble trim thread and remove contaminants 4. Replace the stem nut 5. Correction stem