Pump losing prime
Our sprinkler pump is 2 yrs old. The well has a wellpoint, no foot valve. There is a check valve that has been replaced twice since this problem started occurring. It has been moved from below ground level to above ground level for easier replacement. It is approximately 12-24 inches from the intake of the pump. The pump is losing it's prime overnight. One night we left the pump's priming port open and the pvc pipe above the check valve open so we could observe where there was a 'leak' - was the pump leaking - or the check valve. Neither one lost a significant amount of water overnight - so neither one is leaking independent of the connection to each other. We connected them, ran the sprinkler system, checked the water level in the pump, next morning - checked the water level in the pump - couldn't see any thru the port, closed the port, turned it on and waited ten minutes for it to prime - nada! So we primed the pump again.
We figure it is a faulty check valve because the pump is not visibly leaking and the pipe connections between the pump and the check valve are not leaking. Since we have had the check valve replaced twice already (by professional) we are wondering if there isn't a better quality check valve or some other ???what??? that we could install that will stop the pump's water from evacuating???
Appreciate any help in this area.