I can't figure this out. I have a pool with an attached spa. The water coming over the spillway varies considerably day to day.
From the pump, water branches off to the pool and spa. The spa side has a check valve, so if you have the distribution valve set to spa, it won't backflush into the pool line. I
I thought the check valve might not be opening all the time. I took it apart, and it works perfectly.
If I turn the distribution valve to "spa only", and then turn the valve back to "pool and spa" the amount of water increases barely a trickle to a nice waterfall over the spillway. It will remain that way until the next day, even if I turn the pump off and then back on.
Part of the problem is, I don't understand what happens to the water after it leaves the distribution valve and goes to the spa. I have six jets around the spa. I don't feel any water coming out of those, but maybe there is, just not much.
In the middle of the six jets, is something that appears to be a "blowoff valve". That does have some water coming out of it, but it doesn't seem like enough to account for all the water coming over the spillway when it is flowing properly. Hard to tell.
Then there is a drain on the bottom, and another on the side of the spa.
If anyone can explain spa plumbing (when attached to pool system) to me, it would be greatly appreciated.