"Mikepier" wrote in message
...
All I can tell you is if I pour water in the pipe to the top, it
eventually drains down to its standard level of 2 ft below the
basement floor, so I don't think I have a checkvalve in the vertical
pipe, or if I do, its defective.

I think you do have one, because the old pump would have used one, but from
sitting idle, it's probably frozen closed, with a slight leak