Suction problem?

[CarlD]

I guess it depends on where the plug-up is. Can you pump to waste? If so, it's blocked in the return lines. If you disconnect the skimmer does your low drain work, or vice versa? If neither works you may be blocked further back. Sure you have all the valves on the the filter set to "filter" and not "winter" or "closed" mode?

Generally, diagnosis is by removing a section at a time and seeing if that fixes it. I did this all the time as a programmer.
Supposing you hooked a nice length of hose or TigerFlex to the inlet of the pump and the other end in the water and it NOW started working--you'd know that from pump to return is fine and the problem is from the drain/skimmer lines.
Or you unhooked the pump from the filter and now it pumped water like a fire hydrant! Then it's in the filter or the return lines.
Where does it work? Where doesn't it work?

[cmcq]

Thanks. Through some of the process of elimination you describe, it appears the issue is with the check valve. I removed it, turned in 1/4 turn so the valve isn't blocking the flow of water and everything is fine. Maybe something (age?) is making it too hard for the value to open? That would be strange since it was working yesterday, but who knows. Is it a problem to run without the check valve properly installed?

[Jason in Ky]

Don't know if it is possible to do in this application without seeing the check valve. But make sure you didn't put it in backwards during re-assembly.