The newly installed self-priming pump doesn’t draw water
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The three newly arrived ZW self-priming pumps, under the same operating conditions and not located at the same construction site, failed to deliver water once installed and filled with water – all three pumps exhibited the same issue. I have checked the motor’s rotation direction and the inlet pipe shows no leaks. Do you experts know of any other possible causes? If there were a quality issue, not all three units would be affected. Besides, they were newly installed and haven’t been used once.
Check if it’s a problem with the pump
There is no ball valve near the outlet flange at the upper part of the pump body; it is used to open and release air when the pump is started. It’s possible that there is a check valve in your outlet pipeline, and the low density of air isn’t sufficient to push the valve open.
Another issue is a problem with the pump seal; check the pump’s seal as well as whether the installed head exceeds the pump’s maximum head capacity
Is the installation height too high? Did Yang Cheng make the wrong choice?
What are the pump’s flow rate, head, and speed? What are the dimensions of the pump inlet and the inlet pipe diameter? What is the total length of the suction pipeline? And what is the vertical height of the liquid level above the centerline of the pump shaft? Media name and temperature?
Install a baffle-type check valve at the inlet, raise the liquid level a bit more, then pump the liquid out of the tank and start it up immediately; perform backflow drainage at the outlet to see if flow can be achieved. If that doesn’t work, it’s possible that the pump’s net positive suction head is too low; try making the inlet pipeline larger.
The installation height exceeds the maximum self-priming height; as far as I know, the self-priming height of this type of ZW pump does not exceed 4.5 meters. Additionally, the higher the temperature, the lower the self-priming height
Also, the higher the viscosity, the lower the self-priming height
Pump selection, such as head, or suction height. Height of the suction pipe, presence of a siphon tank on the front side