Air in well pump

[Juraj]

Hi, I have a shallow well in my cellar. It worked, but then the water level dropped. The pump was not used for some time (maybe a year). Then I deepened the well and I replaced the suction pipe for a little longer one. The water level is now about 3.5 meters below the pump. I cleaned the foot valve and water filter. It looks like this:

https://www.dropbox.com/s/ok5vo92yb6gf4uw/20190413_180045.jpg?dl=0

I primed the pump and started it. It works (kind of), it pumps water, when the pressure reaches 4.5 bar, the pump shuts off, when I open a valve and the pressure drops to 3 bar, it starts pumping the water again. But, the filter looks like this:

https://www.dropbox.com/s/52inxgj4369btgm/20190413_171948.mp4?dl=0

What can cause this? The pump is not loosing the prime (when it's not in use) and when the pump shuts off at 4.5 bar, it holds this pressure, and I didn't notice any leakage. The foot valve is fully submerged in the water.

Could you, please, help me? I have no idea how can I troubleshoot and fix this. Thank you very much for any suggestion!

 

[Valveman]

That maybe what the picture shows, but that doesn't mean it is the best or even a good way to do it. I can't understand the language, but it looks like the picture also shows a foot valve plus an additional check valve just before the pump. That check valve can cause you to lose prime, and I would only use a foot valve in this case. The filter, extra check valve, shark bite, and any unnecessary fittings you have on the suction line are just other opportunities for a failure and decrease the NPSH available to the pump. In other words, sucking on the water too hard makes bubbles and air appear. I would bet a simplified suction line with only a foot valve and nothing else will eliminate the air problem.

Basket strainers can be on the suction. But filters with small micron cartridges have too much restriction and should be on the discharge side of the pump.