The water pump does not deliver water
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Question: The self-priming pump at the customer’s site is not pumping water; there is no foot valve. The after-sales team on site says that the pipe sizing is normal and the motor is rotating in the correct direction. I will go to the site tomorrow with the after-sales supervisor to check it out. Since I work in the pre-sales department, I have limited information. I’m posting this to discuss possible reasons why the pump isn’t pumping water and the methods to diagnose it. I have almost no experience in such situations. For now, I’ll share my thoughts; I hope everyone can offer some guidance. Reasons why water isn’t being pumped: 1. First, we should check the motor’s rotation direction and its speed to determine if everything is normal. 2. Check whether the suction pipe is blocked or too small, which could prevent water from being drawn in. 3. Check if there are any air leaks in the suction pipe or the pump body (how to check). 4. It’s possible that the system requires a higher head pressure, and the pump chosen is too small (how to determine this). Is it also possible that the outlet pipe is blocked, preventing water from flowing out (how to check)? These are the only reasons I can think of. I hope everyone can suggest other possibilities. Based on these points, how should we proceed with troubleshooting? I hope experts can guide me on what to check in similar situations and exactly how to do it. The key is knowing the practical steps. I really appreciate any advice you can give. I have almost no field experience, so I can only outline some general points; I don’t know how to carry out the actual checks. I hope everyone will provide thorough guidance, including how to use measurements like current to make diagnoses. Thank you all
First of all, communication leads to improvement; there is no such thing as high or low technology! My personal views are as follows: 1. Check for air leaks; you can only seal the inlet pipe and then perform a pressure test to detect leaks. 2. For self-priming pumps without foot valves, you must first prime and vent the pump before starting it. 3. Check whether the inlet filter is clogged. 4. Check whether the inlet pipeline is too long, exceeding your suction height. 5. If the drive motor is missing a phase or the wires are connected incorrectly, this should be checked; if necessary, measure whether the motor’s speed reaches the rated speed.
Coincidentally, a few days ago one of our self-priming pumps wasn’t pumping properly. We checked all possible areas and found nothing abnormal; it was just the mechanical seal that was leaking. We decided to replace the mechanical seal, and amazingly, everything worked fine after the replacement. Huh, is it possible for the mechanical seal to still leak air? That’s unreasonable.
What type of self-priming pump do you have? Are there solenoid valves on the intake pipeline? The most important thing is to check the exhaust system; only by removing all the air from the suction line can water be drawn in. Exhaust more air at the outlet