Sand in pool after backwash/rinse

[BigDave]

Sorry to ask the obvious, but, is the pump off when you move the valve?

[wizzardz]

Yes, the pump is off when making changes. The air relief line adjustment seems to fit the symptoms - I need to find a diagram so I can determine what needs adjusting.

[BigDave]

Parts Diagrams:
Valve: http://www.hayward-pool.com/pdf/manu...ve-SP0714T.pdf
Filter: http://www.hayward-pool.com/pdf/Part...-Top-Mount.pdf

I don't see an air relief line.

Another thought, is it possible that the multivalve has been disassembled and reassembled mis-oriented?

[PoolDoc]

I don't see an air relief line.

You're right -- my inexperience with top-mount filters is showing!

+ I don't see how you can mis-orient the valve, unless you mean with respect to the piping. Is that what you mean? . . . I have no idea what would happen if you hooked the pump discharge to the filter outlet, and hooked the outlet to the pool return!

+ Another possibility is that the filter was overfilled with sand . . .

+ And, yet another: if anything was done to INCREASE flow through the filter (bigger pump, removed pipe-line obstructions, etc), then sand will leave the filter during backwash, but a small amount will remain in the diffurser and return to the pool when normal flow is restored.

In both cases above, using the rinse position should remove that sand before it can enter the pool.

[BigDave]

What I tried to say was: if the six screws that hold the top valve assembly (handle, top, springs, seals, diverter) were to have been removed, the top of the valve removed (to change spider gasket?) and then put back rotated, the diverter (is that the right name) would be lining up to the wrong ports inside the multivalve. The drawing does look like it's keyed so not likely but it does look like it might be possible to install the handle rotated 180 degrees.

[wizzardz]

There wasn't much of a chance to get the orientation of the new valve wrong. Though I didn't work to try putting it on backwards, its the same orientation as the one that came off it.

Overfilled with sand is a consideration. I've been resisting pulling the rest of the top off because of the plumbing (much would have to be replaced). I think the fixed gasket would create a difference in pressure as the filter sees it (old pressure gauge was out as well, so can't tell a before/after pressure).

Sounds like I might have to bite the bullet and yank the top off the filter to check deeper.

One thing that's tough with this setup is that I don't really have a known good working state to start from. When we bought the house I could tell the old gasket was already bypassing to waste (water missing from pool) or recirc (tough time cleaning). Now that the valve/gasket has been replaced, there could be any number of issues that present when they wouldn't have before.

[PoolDoc]

Before you pull the valve (which is usually a pain on top mount filters), post the make / model of your pump. Note the the number on the electric motor are ONLY for the motor, and not the pump. Pump info is on the 'wet' part of the case.

The reason is, if your pump is oversized for your filter, the solution may be to throttle your pump back. There are several ways to do this.

It would also help if you can post pictures, by linking from Flickr, Photobucket, Picasa or by emailing them to poolforum@gmail.com