Common pump failures and their solutions

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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. Noise 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 low 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 check it. 2 The bearing housing is too hot to the touch, and the ammeter reading is high. 1. Insufficient or interrupted cooling water, or 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. 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 inside the pump or in the suction pipeline. 2. Suction line 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 inside the inlet pipe, 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 inside the pump or in the conveyed medium. 2. Too low liquid level in the suction container. 3. Too low suction line pressure. 4. Obstructions in the suction pipeline. 5. Damaged impeller leading to 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 line 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 from the pump, severe vibration. Metal particles are present in the lubricating oil. Increased current leads to circuit breaker tripping. 1. Insufficient or no lubricating oil in the oil tank. 2. Poor quality lubricating oil, containing impurities or being water-emulsified. 3. Interruption or insufficient cooling water, causing high bearing temperatures. 4. Poor quality bearings or fatigue 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. Incorrect 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 and install the sealing material as specified. 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, handle it accordingly. 7 The centrifugal pump cannot be rotated manually. 1. Heavy oils have solidified (such as residue). 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 open to a low degree). 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. 3. Replace the pressure gauge. 4. Identify the cause and reduce the inlet pressure