Even though it is 8’ from the check valve down to the water level, it should stay full of water. The check valves act like putting your finger on top of a straw full of water. The water can’t get out until you remove your finger and let air in. 9 checks valves leave 9 places to fail. With the power off, if any of these checks leak back, you are going to lose prime. With the power on, the pump should come on and refill the pressure tank, after the water in the tank leaks back through the bad check. So if you leave the power on, the pump will cycle on and off while no water is being used.
Worn check valves always close differently. One time it may seal pretty good. The next time it may not seat in the same place and won’t seal at all. One or all of your check valves is leaking back. The process of elimination maybe the only way to find it.
Worn check valves always close differently. One time it may seal pretty good. The next time it may not seat in the same place and won’t seal at all. One or all of your check valves is leaking back. The process of elimination maybe the only way to find it.