Sand in pool after backwash/rinse

[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

[wizzardz]

Its a Hayward 3007X10AZ pump married to a ST1102 1hp motor

[wizzardz]

Any feedback on if the above equipment is appropriately matched?

[PoolDoc]

In theory, that filter and pump are well matched. Unfortunately, most pool manufacturers tend to oversize pumps and undersize filters. Even though filters are rated higher than 15 gpm/sft, flows over that amount can wash sand out during backwash.

Your S244T filter has 3.14 sft, so it's 15 gpm/sft flow is only 47 GPM.

The SP3007x10 AZ will generate 45 gpm against 60' (or 26 psi) of dynamic head. Depending on your pools layout on the suction side, the dynamic head on simple pool is likely less that that, meaning the flow rate will be higher. One way to get an idea, is to look at the filter gauge when the filter is CLEAN. If it's less than 15 psi, your system is almost certainly running at more than 47 GPM, possibly a lot more.

Add to that the fact that the resistance to flow during backwash is likely lower than during normal operation . . . and there's a good chance you will lose sand during each backwash until the sand level is below standard.

As mentioned before, pictures would help us determine what a good solution for you might be.

[wizzardz]

Below are links to pics. I noticed the gauge is currently reading lower than when I replaced it (was about 15)






Let me know if there are other pics that would be helpful. Your feedback has been most helpful and makes sense.

I believe the psi change I mentioned above may have been before (15) and after (12) the backwash/rinse cycles.

From your description, its sounds I need a way to reduce the GPM rate. Any suggestions on how that may be accomplished? I'm guessing since the old gasket was partially blown out, it was reducing the flow by bypassing some to waste or recirc. (or the higher rate helped blow out the gasket)

thanks again

[wizzardz]

Decided to pull the top off the filter and check the laterals/sand/etc since the pool refused to clear up. Valve assembly pretty much lifted out easy enough...almost too easy.



Besides the tube being broken, I pulled the rest of the old laterals and they were just crusted over and one was missing. Fortunately I had decided to get new laterals and sand. The filter is draining very slowly so I'll have to wait overnight before I start pulling the old sand.

Whats the best couplings to use on the PVC to allow easy disconnections in the future?