Pressure just builds......

[cmcq]

AJ, here might be the problem, Hayward makes some of the best equiptment out there, unfortunately they don't know how to use it. To backwash your unit correctly:
(Obviously, turn off the pump when changing multiport positions)
Put the multiport on backwash, and watch the sightglass for ~clear.
Rinse the filter till it is ~clear.
Repeat until the 'backwash' cycle is ~clear and rinse again. (~3-5 cycles)
Put it on filter for ~ 1 min. and do another backwash/ rinse cycle.
At this point, you've gotten ~80% of the de out, so only add 80% back in, in your case, it's a little under 4#.
Having way too much, or too little, de in the filter can cause the problem you are experiencing and hurt the unit. Try this a couple of times before you replace the grids.

I'm having the same problem (pressure building quickly w/ DE filter) have a few questions.

First, should I bother with the backwash process you describe or just proceed with cleaning the grids now, and use that process in the future?

Second, and more of a newbie question, I have 2 valves I turn when I backwash. The first is a "turn and pull" type valve in front of the filter (is this the multiport?) and the second is an in-line "bypass valve" between the filter and the separation tank. In your instructions, you mention the normal backwash instructions (3-5 cycles until clear), but then you say "put it on filter for 1 min." Does that mean to close both the bypass valve and the multiport valve just as you would when you finish backwashing?

Thanks in advance

[waste]

Cmcq, first let me say congrats on comming here to keep money grubbing pool guys (like myself ) out of your wallet!
I have very limited experience with your type of valve (it's not a multiport in the sense I was describing, I've always heard of them as 'push/pull' valves), however the process should still work - the idea is to run the water flow backwards through the filter to 'kick the crud off the grids' and out onto the lawn. I can't quite picture your set-up, but yes, before the final 'backwash' turn whichever valves you need to back to 'normal' filtering for ~ a minute.
You might want to consider starting your own thread on this topic as there are probably others here with more experience than I for your type valve and they may be able to give you better advice. However you handle it, know that I'll always make myself available to help you - Waste