Last weekend we got into our new pool and while swimming I noticed that I could feel no flow into the main trains when I dove down to them and covered them with my hands. Since our PB installed 4 main drains I didn't think too much about this, but decided to perform some more tests.
First, I took a small piece of grass and placed it next to and on top of all 4 different drains. The grass floated away from the drains in each instance. I then decided to turn off my skimmers and only have the main drains supply the pump. This is what happens when I do that:
Each skimmer is connected with its own 2" line to the pump pad and the 4 main drains all share one 2" line back to the pump pad.
The PB has come out and says everything is working normally, but I am not convinced.