Common pump failures and their solutions

Thread Content

Serial Number Fault Phenomenon Cause of Fault Solution 1 Significant fluctuations in the reading of the pressure gauge at the pump outlet, as well as fluctuations in the ammeter reading. A cracking sound is heard inside the pump body and pipelines. The flow rate at the pump outlet decreases significantly. 1. Air leakage in the pump’s suction pipeline. 2. Blockage in the inlet pipeline or insufficient valve opening. 3. Insufficient inlet pressure. 4. High medium temperature causing water vaporization. 5. Low medium temperature resulting in high viscosity. 6. Clogging of the impeller. 7. Motor running in reverse direction. 1. Remove air from inside the pump. 2. Open the inlet valve wider or clear the pipeline. 3. Increase the inlet pressure. 4. Slightly lower the medium temperature. 5. Slightly reduce the medium’s viscosity. 6. Contact a mechanic for inspection and repair. 7. Have an electrician conduct an inspection. 2 The bearing housing is abnormally hot to the touch, and the ammeter reading is high. 1. Insufficient or interrupted cooling water supply, or too high cooling water temperature. 2. Insufficient or excessive lubricating oil. 3. Damaged bearings or abnormal bearing clearance. 4. The oil slinger is no longer functional. 5. Water enters the bearing housing, causing the lubricating oil to emulsify and become contaminated with debris. 6. Excessive load on the pump. 1. Provide more cooling water. 2. Add lubricating oil or adjust its level to 1/2–2/3. 3. Contact a mechanic for repairs. 4. Contact a mechanic for repairs. 5. Replace the lubricating oil in the bearing housing. 6. Reduce the load according to the process requirements. 3 Vibration of the centrifugal pump. 1. Air present inside the pump or in the suction pipeline. 2. Suction pipe pressure is less than or close to the vaporization pressure. 3. Unbalanced rotor. 4. Damaged bearings or excessive bearing clearance. 5. The pump and motor are not aligned properly. 6. Collision or friction between the rotor and stator components. 7. Loose impeller. 8. Debris present in the inlet pipe, inside the impeller, or within the pump. 9. Resonance in the pump’s foundation. 1. Refill the pump and remove air from inside the pump or pipelines. 2. Increase the suction pressure. 3. Rebalance the rotor. 4. Replace the bearings. 5. Realign the pump and motor. 6. Realign the rotor components. 7. Inspect the impeller. 8. Remove debris. 9. Eliminate resonance in the foundation. 4 Cavitation in the centrifugal pump. 1. Air present inside the pump or in the conveyed medium. 2. Too low liquid level in the suction container. 3. Too low suction pressure. 4. Obstructions in the suction pipeline. 5. Damaged impeller, resulting in reduced suction capacity. 1. Refill the pump and remove air from the pipelines. 2. Raise the liquid level in the container. 3. Increase the suction pressure. 4. Clean the suction pipeline. 5. Inspect and replace the impeller. 5 The shaft of the centrifugal pump gets stuck; high temperature in the bearing housing, abnormal noise and severe vibration from the pump, presence of metal particles in the lubricant, increased current leading to tripping. 1. Insufficient or no lubricating oil in the oil tank. 2. Poor quality lubricating oil, containing impurities or being emulsified due to water. 3. Interrupted or insufficient cooling water, causing high bearing temperatures. 4. Poor quality bearings or fatigue and aging due to prolonged operation. Switch to the backup pump immediately. Stop operating the pump and inform the control room. Contact a mechanic for repairs. 6 Seal leakage. 1. Improper selection or installation of the sealing material. 2. Worn-out sealing material or loose gland. 3. Damaged mechanical seal. 4. Insufficient cooling water or seal oil in the seal chamber. 5. The pump has been running dry for a long time. 1. Select the appropriate sealing material and install it correctly. 2. Contact a mechanic to replace the sealing material or tighten the gland. 3. Contact a mechanic to repair the mechanical seal. 4. Adjust the amount of cooling water or seal oil in the seal chamber. 5. If the pump is running dry, address the issue related to dry running. 7 The centrifugal pump cannot be rotated manually. 1. Heavy oils have solidified (e.g., residue oil). 2. Stuck due to lack of rotation over time. 3. Damaged or stuck pump components. 4. Severe shaft bending. 5. Excessively tight packing in the stuffing box. 1. Purge and preheat the pump. 2. Increase the frequency of manual rotation (to preheat the pump). 3. Contact a mechanic for repairs. 4. Contact a mechanic to replace the shaft. 5. Contact a mechanic to loosen the packing gland or increase the frequency of rotation. 8 Outlet pressure exceeds the specified limits. 1. Blockage in the outlet pipeline. 2. The outlet valve plate has fallen off (or is not opened fully). 3. Faulty pressure gauge. 4. Excessively high pressure at the pump inlet. 1. Address the issue with the outlet pipeline. 2. Inspect and replace it if necessary. 3. Replace the pressure gauge. 4. Identify the cause and reduce the inlet pressure