My pool plumbing system is pretty simple: one skimmer, two returns, and a main drain. I have a DE filter, and it (obviously) has input and output pipes. I can't tell by looking at it which is which. I can follow the water from the pump to the multiport valve, but from there I'm lost. Because I don't have a lot of extra things like a spa and fountains, I don't have lots of valves to deal with like most of the videos on Youtube show. The best video I've seen so far demonstrates how to blow out the lines using a shop vac at the filter output pipe. But how do I figure out which pipe is the output?
Then, that will only help me for blowing out the returns. How do I blow out the skimmer and main drain? From the videos, it appears there would be a valve to open and shut, but my system doesn't have one. I'm guessing I should set the multiport valve to a specific setting, but have no idea which one.
Some posts I've read make it seem like I could (or should) blow out my lines from the skimmer, but I can't figure that one out at all.
I've done a lot of research here about closing my pool, and much of it is making me more confused than ever. I'm starting to feel like an idiot, because what is obviously not that difficult is seeming incredibly complicated, and I can't find simple answers. Mostly it's about blowing out the lines, which if I screw up, could be a very costly mistake. I'm starting to get really nervous about it.