What Are The Troubleshooting Methods For Multi-stage Centrifugal Pumps

Jan 04, 2026

Nowadays, the types of water pumps are becoming more and more complete. For example, multi-stage pumps are a type of water pump with comprehensive functions. However, when using this type of water pump, there may be some common faults. So, how should we deal with many common faults?

 

1. Faults and solutions of multi-stage centrifugal pump balance device

When there is excessive wear (usually exceeding 2mm) or unevenness on the balance disk and balance ring, first flatten the grooves where they are worn, and add shims behind the balance ring to compensate for the reduced thickness. The added gasket must be uniform and flat, and should be replaced if it is worn out excessively.

 

2. Malfunctions and Solutions of Multi stage Pump Impeller and Mouth Ring

If the blades of the water pump impeller are damaged due to cavitation or solid impurities suction, and the wear of the mouth ring is too great to repair, the impeller should be replaced; If there is only slight wear at the impeller mouth ring, it can be repaired. The method is to thread the impeller through the groove at the impeller mouth ring on the lathe with a core shaft, and then determine the inner diameter size of the sealing ring based on the size of the impeller mouth ring after turning it small. The gap between the impeller mouth ring and the sealing ring is determined by the inner diameter of the sealing ring, generally taken as 0.3-0.5mm, while the outer diameter of the sealing ring remains unchanged.

 

3. Faults and solutions of multi-stage pump shaft seal device:

(1) When repairing the water pump, the packing must be replaced, and other parts must be cleaned and inspected.

(2) When the shaft sleeve is worn out of the groove by the packing, it should be replaced or welded and then repaired by turning.

(3) When installing the packing ring, it must be aligned with the water seal hole to avoid being blocked by the packing and causing the water seal to lose its function.

 

 

4. Faults and solutions of vertical multi-stage pump shaft

The pump shaft is the core component of the rotor, which is equipped with impellers and shaft sleeves and rotates at high speed in the pump body.

The pump shaft can be repaired and used as long as there are no cracks or severe surface wear or bending. The bending amount of the shaft should not exceed 0.06mm. If it exceeds this value, it should be straightened. It is best to use a screw press without heating for straightening.

 

5. Fault and solution of axial displacement of multi-stage pump rotor

The alignment between the inlet of the pump's guide vanes and the outlet of the impeller is crucial and affects the performance of the pump. The inspection method is to check the rotor runout after assembly. The total runout of the 6-10 stage pump should be 1.0-2.0mm. If the axial runout is large, it is allowed to add a smooth and evenly thick adjustment pad between the balance plate and the balance ring for adjustment.

 

6. Faults and solutions of multi-stage pump bearing body

The bearing body is generally not damaged, but in case of improper fit or poor installation that enlarges the shaft hole, first use a boring machine to enlarge the bearing hole (to ensure concentricity), and then insert a sleeve with an outer diameter that matches the bearing hole and an inner diameter that matches the outer diameter of the bearing.

 

7. Severe vibration or noise generation

In the process of using a stainless steel multi-stage pump, various problems such as severe vibration or noise may occur. In this case, if you want to repair this fault, you must first understand the cause. The reason for this situation is usually due to the multi-stage pump not being installed firmly or not being installed in the correct position.

 

 

On the other hand, if the multi-stage pump motor ball bearing is damaged, some noise may also occur. In the face of this fault, when repairing, it is necessary to further stabilize the pump through appropriate methods, and at the same time, find a way to lower the installation height of the pump. If it is caused by the damage of the motor ball bearing, then it is necessary to timely fix it. Replace the motor ball bearings, This is the only way to solve problems in a timely manner.

 

8. Overheating of transmission shaft or motor bearings

This is also a common problem that may occur during the use of multi-stage pumps. One very important reason for this situation is that excessive consumption of lubricating oil during the use of multi machine functions can result in insufficient lubricating oil. In this case, huge frictional forces may be generated, leading to overheating of the transmission shaft or motor bearing. On the other hand, if the bearing ruptures, it may also cause this problem. Therefore, when repairing multi-stage pumps, it is necessary to add some lubricating oil or replace the bearing in case of bearing rupture. If the motor bearing or transmission shaft continues to be used in case of overheating, it is likely to cause damage to various spare parts in this situation. The, This will have extremely serious consequences.

After reading the introduction of this article, you should be able to know what faults often occur in multi-stage pumps during use, and you should also know the reasons for these faults and their solutions. If you often need to use this type of pump, then you must learn more about this knowledge.