What are the reasons for low outlet pressure and low current in a centrifugal pump?
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The centrifugal pump has a rated flow rate of 280 m3/hr, a head of 30 m, and a rated current of 85.4 A. However, during operation the outlet pressure is only 2 barG and the current is 42.5 A. Could anyone tell me what the reason for this is? This is the hot water circulation pump; it has not yet heated up.
The outlet pressure is low and the current is low; check whether the pump is vibrating, and also verify if there is any blockage at the pump’s inlet； Check whether the inlet valve opens properly ； Check whether the impeller is loose; if it is connected by a key, check whether the key is in good condition ； Check whether there is any blockage in the impeller flow channel and whether the blades are damaged ； Is there a mouth ring, and is it severely worn? ； Check if the motor is faulty
I’m not sure whether it’s a problem that occurred during the testing phase or one that appeared the day after; it could be due to the following reasons: you didn’t specify the actual flow rate of the pump, gas remained inside the pump, or the filter at the pump’s inlet is clogged. The system is not completely filled with water. It is recommended to start the pump in accordance with the specifications: open the inlet valve fully and close the outlet valve fully. After starting the pump, gradually open the outlet valve while ensuring that the rated pressure does not drop. If the pressure begins to decrease, stop opening the valve for a while and observe the water output or pressure changes. If the pressure stabilizes after some time and starts to rise again, then the outlet valve can be gradually opened further. It is also necessary to observe the changes in strength (for reference). I guess it’s because the system isn’t filled with water.
What is the outlet flow rate? Check whether the inlet filter is clogged, resulting in insufficient inflow, and also see if the air pump is releasing air and whether the pump exhibits vibration due to vacuum conditions. What is a medium?
After cleaning the filter and releasing air, the pump’s pressure increased, but the current was still only 52A
After venting and cleaning the filter, the pressure in the pump increased, but the current remained low at only 52A, during the testing phase
This post was last edited by backcat666 on 2018-3-21 at 18:16. Is the impeller installed in the wrong direction? Is the impeller cover loose? Are the motor connections reversed? Is there a fault with the motor? Is the pump inlet blocked? Was the pump filled correctly? Are the check valves at the inlet and outlet functioning properly? Is the clearance around the impeller’s mouth ring within the standard range? When the pump is operating, it may not reach its rated flow rate; therefore, the current may not reach its rated value! The characteristic curve of the pump and the characteristic curve of the pipeline together determine parameters such as flow rate, head, and efficiency at its operating point!
Has the traffic been reached? If the flow rate is not sufficient, is it possible that the inlet or filter is blocked, preventing air from entering?
Has the inlet pressure of the pump not reached the required level? The outlet pressure is also low; in some pumps, the outlet pressure is related to the inlet pressure. Check the pipelines again to see if there are any blockages or if the valves aren’t fully open. Once the flow rate increases, the current will naturally increase as well.