I need help; I earnestly ask all experts for their assistance. Thank you very much
Thread Content
There are three water pumps: pumps No. 1 and No. 3 operate at power frequency, while pump No. 2 operates at variable frequency; they are connected in parallel. All of them have a head of 60 meters. When the factory-installed valves are closed, a pressure of 1.1 MPa can be achieved, but even when the valves are opened and the pumps operate at full load, only 0.16 MPa can be attained. Two valves are installed outside the main valve: one with a range of 5 meters and another with a range of 100 meters. Pressure cannot be generated even when these valves are closed; the normal supply pressure should be 0.35 MPa. For another set of equipment, closing the factory-set valve results in a pressure of only 0.48 MPa, while keeping the valve open allows the pressure to stay at 0.35 MPa. What could be the reason for this? I have consulted many professionals; some suggested checking the impeller and motor rotation, as well as the piping system, but the cause has still not been identified. The equipment supplier and the pipeline construction team have checked the pipeline system multiple times, shifting blame on each other. I’m an outsider seeking help; I need to determine the cause before I can find someone to fix it.
What is the water supply pressure? Where does the water come from on the supply side?
Is the inlet clogged? Thank you
Try it by closing the main valve at the sub-station! See which one is boring
Look at which pump has the lowest current, and focus on checking that one
Water supply insufficient at 0.35 MPa
Open the inlet valve, slightly open the outlet valve, then start the pump; once the pressure stabilizes, gradually open the outlet valve further.
The key issue is that after starting the pump, the outlet valve must be adjusted so that the outlet pressure of the pump itself remains at the operating pressure; in other words, the valve should be left slightly open, as mentioned by the technician earlier. Once the system is completely filled with water, it can be used normally. It is advisable to install a pressure gauge in front of the pump’s outlet valve, ensuring that the pressure remains at or above the operating pressure; once the system is fully filled with liquid, the desired level of pressure can be adjusted properly.