Overflow Drain?

[Rocketfish]

Thanks for the input Ozzy. It DOES seem to do the job of skimming now that I cleaned out all the leaves. I removed the weir because #1, it kept getting stuck every few days (it was a universal spring loaded version), and #2 I usually have a solar cover on so didn't really need it. I need to rethink it all, now that it's winter and I packed the cover away.

 

[verogal]

Is there a grated cover with a pipe behind it by the skimmer opening?

I was wondering if we had an overflow drain, because I was filling up the pool by hose and forgot about it! But it didn't flood. We do have a grated cover over a pipe near the skimmer, so that might be an overflow? But it's a bit below the bottom level of the skimmer. How does it work?