Help with my pump / filter configuration

[rgn22]

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/r61 ... _whole.jpg

Close-Ups of the 2 valves:
http://i1174.photobucket.com/albums/r61 ... valve1.jpg
http://i1174.photobucket.com/albums/r61 ... valve2.jpg

 

[JasonLion]

4) This valve chooses between two suction locations. Presumably pool and spa based on the pipe label.
6) This valve chooses between two return locations. Presumably pool and spa.
8) That is probably an air intake for the spa jets.

 

[rgn22]

Great, thanks for the fast response.

I have some follow-up questions, if you don't mind. Right now, with the valves in the positions that you see, there are return jets in the spa and the pool. Both are getting returns. So if the one valve chooses between pool and spa, how could they both be getting returns?

Also, do these valves need to be adjusted before backwashing and rinsing using the multiport valve? I read somewhere to make sure your valves are open before backwashing, or you could cause serious damage. But I'm not sure this would apply in my case.

 

[JasonLion]

Both valves are set to close off one pipe and send all of the water to the other pipe. On the suction side the pipe labeled spa is turned off. On the return side they are not labeled.

There are a couple of possibilities. It is fairly common to plumb the pool side so that it always sends at least a little water towards the spa, so the spa will not stagnate. The plumbing to do that is not visible, but it might be underground. Another possibility is that the valve is broken, or the handle might be installed on the valve in a non-standard way (tricky to do, but I have seen it happen before).

 

[rgn22]

That sounds logical. I suppose I could turn the pump off, switch that return valve to the other side, and see what happens. If more flow goes to the spa, then I'll know. Thanks for the help! I really wanted to know about these valves before doing anything.