I have been reading as much as I can and have got a pretty good handle on pool care, but there are some valves on my pump / filter and I don't know their purpose. Before I backwash or do anything, I'd like to know what they are for, and if I need to adjust them first. Specifically there are 2 valves and a pipe that I need help with.

I have a 36 sq ft DE filter, a 1.5 HP pump, and an 18,000 gallon pool with a spillover spa.

Below are photos of my system. I have numbered them as follows:

1) DE Filter
2) pump
3) Filter basket
4) Unknown valve *
5) Chlorinator compartment
6) Unknown valve *
7) multiport valve
8) unknown pipe *

* I need help with these

Thanks!

Photo of whole configuration:
http://i1174.photobucket.com/albums/...pump_whole.jpg

Close-Ups of the 2 valves:
http://i1174.photobucket.com/albums/...n22/valve1.jpg
http://i1174.photobucket.com/albums/...n22/valve2.jpg