Pump will not create pressure

[Mitchell911]

I have an inground pool system that has new pumps and motors about 3 yrs back.

Recently replaced ORing on filter tank. System built pressure up immediately. Several days later I go out to the pump room and there is no pressure. I reinstalled the ORing that I just replaced- double checked the pump strain cap to be sure it is tight. Nothing seems to be able to get pressure up again. Does not appear to be any water leaks and cannot detect any air leaks.

Any suggestions on what to check for or something I may have just forgot to do?

Thanks

[PoolDoc]

Pressure is what shows up on a gauge; flow is what comes out of the return. It's possible to have high or low pressure with no flow; it's also possible to have good flow with little pressure.

Are you lacking pressure, or flow, or both?

. . . cannot detect any air leaks . . .

Finding suction leaks is hard; finding out that you HAVE a suction leak is not so hard. Is there air in your pump strainer basket when the pump is on?