Hi all, I need help identifying my plumbing lines. I've had a pool for 3 years (was already installed when I bought my house) and I though I have a good handle on BBB chemistry, I need some help understanding where all the pipes go and what they're doing. I'm fairly handy--changed my SWG cell by myself, changed the sensor, and most recently attempted a deep wash of my sand filter. That's how I found out I don't know as much as I thought. I tried to close off the water inlets and outlets to keep the water inside the filter so that it would run over the top, but it never did. It went out the waste pipe, and I could never get that closed off. Here is my setup and what I think things are...can you take a look and see what you think? I'm afraid to turn pipes on or off for fear of seizing something up.
2 main drains in bottom of pool, 2 skimmer baskets, 4 returns, 1 dedicated vacuum return, 1 bubbler, 2 fountains, there is an in-line puck chlorinator that don't use:
What I think it is:
A - out to fountains for sure
B - out to bubbler for sure
C - out to 4 returns?
D - in or out to top of vacuum booster pump?
E - in from main drain or skimmers
F - in from main drain or skimmers (I could close one off and see which it is, if I'm right so far)
G - small pipe flowing in or out from front of booster pump?
H - out from sand-filter multiport snakes around back to SWG
J - out to waste for sure, though I cannot turn the blue valve at all
K - out from main pump to bottom of sand-filter multiport
L - in or out from middle of sand-filter to bottom of multiport?
M - in or out from lower on sand-filter to bottom of multiport?
N - random 1" capped PVC sticking out of the ground--maybe plumbed for heater?
So does the water come from the pool via E and F, through the pump, through K into the multiport, (something happens here with L and M), out the sand filter through H to the SWG, then back to the pool via A, B and C? Do I have the basic flow correct? Where do the booster pump pipes come into play, and how? Also, when it comes into the sand-filter, I understand that it comes in at the bottom, shoots through an internal pipe to the top where it is sprayed on the sand and filters thru, but I don't know how L and M fit into that process.
Also, the two small black multiport levers between A-B-C and E-F will move to bottom, left or right, but will not move to "close" the main pipe coming into them. Is this correct, and why are they not "4-way"?
If you've made it this far I thank you! This is the last piece of my understanding of a pool! (haha, as if).