pressure problems with new de filter

[coryinsocal]

here's a picture, i blame the mess on frustration, and i assure you, it never looks like this unless i've spent a good couple of days saying bad words...

***see prior post for why i added the pic.

[coryinsocal]

well, after a bunch of research, and theorizing, i've decided that the zero pressure reading was correct, yet the filter is operating correctly. a couple things are giving me low pressure. for one, i'm missing the 3 psi due to the scabbed on return. second, since i'm starting with all the small pipes, i'm guessing that my gpm is down in the <25 range. if you go to the pentair manual, they spec the 36 sqft de at 90gpm, giving it a pressure drop of about 6 psi in addtion to the rest of a standard system. at 25gpm, the curve shows less than 1psi drop across the filter. that, coupled with me only having ever put about 80% de in, gives me 0psi drop. i figure now i can cut off that ugly return addition and have a base pressure of about 4psi. does anybody see any real issue with this? i'm curious if this logic is right.

i guess the moral of the story is that, while most people say you can't oversize a filter, you can oversize it such that the pressure differentials are very small. maybe i'll have to clean it everytime it gets 5 psi over clean...

[Poconos]

Just a comment on the pipe diameter pic. The 90 on the left looks like a drain/waste 90 deg. These are not designed for pressure. Sched-40 pressure fittings look like the 90 on the right. The PVC is thicker and the bonding length, how far the pipe goes in when assembling, is about 1.25" I believe.
Al

[coryinsocal]

Just a comment on the pipe diameter pic. The 90 on the left looks like a drain/waste 90 deg. These are not designed for pressure. Sched-40 pressure fittings look like the 90 on the right. The PVC is thicker and the bonding length, how far the pipe goes in when assembling, is about 1.25" I believe.
Al

yeah, i just posted that for the flow rate ref. it's a case study by edison. all my stuff is sched 40.