After a while, the self-priming pump can no longer prime on its own and water needs to be added
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Hello everyone. The self-priming pump on site will operate automatically when the liquid level is high. Once the water has been pumped out, it is unable to prime by itself after a few days, and DC power must be used for refilling. Is there any solution to this problem? If water needs to be added every time, what’s the point of automatic operation? 1. Is it a problem with the installation location of the check valve? Inlet installation? 2. Does the pressure gauge on the pump lose pressure shortly after water is pumped on-site? Is it related to internal leakage of the check valve? Have any friends encountered the same problem? Please help provide answers and offer your analysis and judgment. Thank you
1. Has the imported filter been cleaned? 2. There is a setting to start the pump at high liquid level; is there also a setting to stop the pump at low liquid level? If a pump shutdown mechanism is designed for low liquid levels, it is recommended not to set the shutdown point at 0, but to leave some margin. 3. The basis for judging the second point is that you said the pressure gauge will return to zero after pumping is completed; this means that the water in the inlet tank of the self-priming pump will also be pumped out, which could result in the pump not being able to deliver fluid when it is started again. Therefore, it is necessary to address this issue by adding water back.
There are two factors worth paying attention to in this situation: one is whether the check valve is leaking, which needs to be confirmed. Second, whether impurities in water can cause leakage inside the check valve. For reference.
The check valve on the outlet is leaking, causing the fluid to flow back into the underground tank?
1. The check valve at the pump’s outlet is fine, but it is recommended to install a foot valve (one-way valve) at the pump’s inlet. 2. The situation you described indicates that the pump has run out of fluid – the liquid level in the tank is too low or there is no water at all – which is why there is no water available each time the pump stops; a tank pump is needed in such cases. It is recommended to add a larger siphon tank in front of the pump, and try raising the shutdown liquid level by 20%.
1. It has been cleaned and is very clean; it is in the debugging stage, with industrial-grade pure water being used, so there are no issues. 2. It stops when the liquid level is low; there is still some remaining liquid, so it won’t get emptied completely. I tried pumping out some water from the tank, but after 2-3 days I could no longer pump any more water and had to add more. 3. It doesn’t get emptied completely. Logically, there should be a check valve before the outlet pipe, so the pressure shouldn’t build up, right? 4. Thank you for sharing, bye-bye!
1. All 1.7 units are the same; the valves are still from Hitachi, so they can’t all be leaking. 2. There will be no impurities, as industrial pure water is used during the debugging phase.
1. The owner now wants a water pipe to be installed for replenishing water； Then what’s the point of automatic start-stop for the pump? I need to think of another good solution; perhaps adding something at the pump inlet. Do you have any practical experience with this? 2. Regarding this setting, my description might have been a bit misleading.
I took a close look at the picture you sent just now and noticed something that might be a problem. Are the outlet ball valves of your pumps fully open? ? ? If so, try turning off half of them first to see the effect; I’m waiting for your confirmation!
:victory: Go and give it a try this afternoon
Solve the problem at its root by finding ways to ensure that there is enough water at the pump’s suction inlet even after the pump is stopped. One option is to add a tank, and another is to raise the liquid level when the pump is shut down; we here once proposed making changes to 3 pumps. Add a tank; when the liquid level in the pool reaches 0, water remains in the tank after the pump is stopped, which can be used to start the pump again. Raising the liquid level when the pump is stopped can ensure that the pump does not experience vacuum under normal conditions.