Common Centrifugal Pump Problems and Solutions
Centrifugal pumps are some of the most common types of pumps used in industrial applications because they are designed to be low-maintenance, high efficient, and simple to operate. The fact that they are widely used doesn’t mean that you won’t run across any issues. Here is what you need to know about these pumps, who uses them, and the most common problems with centrifugal pumps and their possible solutions.
What Is a Centrifugal Pump?
A typical centrifugal pump is constructed of a rotary pump shaft with one or more impellers attached. As the impellers rotate in sync, the pump converts enough energy to move fluids in the desired direction.
Centrifugal pumps can be radial or axial, with radial pumps pushing energy through downstream piping and axial pumps generating a suction lifting effect with the impellers. Either are simple enough processes, but something could go wrong. When that does, you’ll need to troubleshoot and fix the problem.
Different Applications for Centrifugal Pumps
Centrifugal pumps are commonly used in various industrial, commercial, and domestic markets. Examples of centrifugal pump applications include:
- Fire protection systems
- Food and beverage manufacturing
- Water supply for residential areas
- Sewage/slurry disposal
- Oil and gas industrial operations
- Chemical manufacturing
Common Centrifugal Pump Problems and Solutions
If your centrifugal pump stops working as it should, is it time to replace it or call in a professional? Neither may be necessary if you can figure out the problem and solve it independently. Here are some of the most common centrifugal pump problems and solutions.
1. Pump Running Dry
If you are not getting any flow after starting your centrifugal pump, there could be several different causes and remedies.
- Air in pump — Ensure the pipework and pump are completely filled with liquid.
- Suction lift is too high — Check for any obstructions in the inlet and verify that static lift is correct.
- Operation reversed — Check the direction of the impeller rotation to ensure it isn’t reversed.
- Incorrect speed — Check the power supply voltage and frequency and confirm that the motor doesn’t have an open phase.
- Clogged parts — Check and clean the valve, impeller, and strainer.
2. Reversed Impeller Rotation
Impellers rotating in the wrong direction is a common problem with centrifugal pumps. If the impellers turn the wrong way, they could cause severe damage to the pump. When wiring power to the pump’s motor, it’s critical to verify which way the motor turns. You can “bump start” the motor to do this.
3. Pump Leakage
Another common problem with these types of centrifugal pumps is leakage. When materials escape the pump and create a mess, this is a serious issue. Excessive temperature, corrosion, or pressure can loosen the joints and seals, allowing fluid and debris to escape.
But there may be a simple fix. Stopping your leaky pump could be as easy as tightening the fasteners surrounding the joints. In other cases, however, you may need to replace a gasket or mechanical seal.
4. Slow Pump Re-Priming
There is probably something wrong with your pump if it takes too long to re-prime. The most common cause of a slow re-priming pump is excessive clearance, leading to inefficiency and overheating. But other possible reasons exist as well, such as a leaking gasket, a clogged recirculation port, or a worn-out volute.
5. Pump Seizure
Pump seizure can happen for several reasons, including foreign objects entering the pump, low flow operation, and off-design conditions. Inspect the pump for foreign objects and debris first and then check the impellers and power source.
6. Pump Vibration
When you begin to see the pump vibrating too much or notice usual noises coming from the device, this could signify a serious issue. Often, vibrations and noises tell you that you have failed bearings or a foreign object stuck inside the pump.
Start with the most straightforward thing first and look for debris or foreign objects. When noises and vibrations occur together, the pump could be experiencing cavitation and may need to be examined by a professional.
7. Debris in Pump
Debris in your pump can create havoc with many of its parts and systems. If your pump isn’t pumping or is less efficient than you want, check for a clogged suction pipe or debris in the impeller.
8. Pump Driver Overloaded
In centrifugal pumps, overloading occurs when the driving motor draws excess current, which results in greater than normal power consumption. Pumps should start with a minimum load with discharge valves open. If the power drawn by the pump increases too much, it may ultimately lead to tripping or overloading of the motor. Some of the most common causes of pump driver overload include:
- The speed of the pump is too fast
- An oversized impeller was installed
- Worn or damaged bearings
- Processing liquids of higher viscosity
- Bent shaft
- Misalignment between driver and pump
- Mechanical seal putting too much pressure on the seat
- Stationary parts coming into contact with rotating parts
- Pump operating too far out of optimum range
9. Poor Efficiency
If you notice that the pump isn’t operating efficiently anymore, meaning it’s taking too long for it to pump out fluid, some of the most common causes of this problem include the following.
- A leaky gasket
- Incorrect impeller rotation
- Damaged or worn impeller, worn-out ring, or damaged wear plate
- An open bypass valve
- Blockage in pump inlet, discharge line, or impeller
10. Chemical Compatibility Issues
If your centrifugal pump has become corroded, it could be due to a chemical compatibility issue. The wetted parts of a pump can be made from a variety of materials — ceramics, metals, thermoplastics, and elastomers. The resistance of these parts to various liquids, chemicals, and temperatures will vary. So you must select a pump designed with your particular application in mind.
11. Bearing Overheating
Centrifugal pumps should not feel hot to the touch. When they do, this is a sign of trouble and something you want to address immediately. There may be a blockage in the suction strainer, the recirculation port, the valve, or the open-ended discharge line. The pump will be less efficient if you ignore the issue and may eventually fail.
There is a wide range of centrifugal pumps available that will give your operation the fluid-transfer services it needs over the long term. These are excellent, low-cost solutions for most high-capacity, low-pressure situations. But if your centrifugal pump isn’t operating efficiently or at all, this list of common problems may help you troubleshoot the issue.
If you cannot troubleshoot the issue with your centrifugal pump or don’t feel comfortable handling it yourself, we have resources to help you. If you aren’t currently experiencing any problems with your centrifugal pump, then it is a great time to look into preventative maintenance to ensure issues don’t arise in the future.