StaRite System 3 Problems

I have a 300lb Sta Rite System 3 sand filter which was spitting sand into the pool through the return after I last backwashed the filter. I opened the filter and, sure enough, two of the laterals were loose in the filter.

However, neither of them were broken. So I reinserted them, and pulled up on them slightly, and they levered right out of the center manifold. I pushed down and they stayed firm. I then checked the others, and they stayed firm when I pushed down or up.

So, I tried switching the laterals with ones that were firm, and it was clear that the problem was not with the lateral (upon inspection the lateral seemed totally fine) , but with the center manifold in those two slots. The laterals are a much "looser" fit in those two slots...so I took some electrical tape and wrapped the lateral where it goes into the manifold (a couple of turns) to try and firm it up. It certainly felt more snug.

I set the pump to "filter" and the system seemed to work fine. I cleaned all the sand out of the pool. But then I backwashed, and then set it to filter again, and, sure enough, sand was spitting into the pool.

Pretty obvious the problem is the center manifold, but it was not obvious to me how to change it. The center piece was pretty firmly installed...my inclination is to have the dreaded pool co fix it, but I am sure it will cost a LOT of money to do so. Any thoughts?

Ian

PS. I just have the multivalve set to recirculate for now, i assume this means i am just bypassing the filter...right?