Pentair FNS DE 48 | Pressure Required

[Barkyman]

Hi

I just started my system up last week with a Pentair DE FNS 48 and I had a question about the pressure.

I am running my VSP daily at around 2200-2400 RPM and noticed the pressure is pretty low ~5. All the fins were new and I added in the approximate amount of DE if not slightly less for the first go around.

After a week, should I add in a little more DE or just let things run. Wasn't sure if there is anything that I should do or if the low pressure is common for new filters.

 

[Jimrahbe]

Barky,

My filter pressure is about 1 lb. because I have a large cartridge filter and my pump runs at about 1200 RPM.

Filter pressure is not what most people think it is.. It is really the amount of effort it takes to force the water through the filter and plumbing and back to your pool. Higher filter pressure means it is harder to force water through the filter. It does not measure of how well your pump is working. The lower the pump speed, and the cleaner your filter, the less the pressure will be.

I say you are good to go with what you have.

Thanks,

Jim R.

 

[Barkyman]

Perfect - Thanks!

It's pretty tough to get the DE amount exact so maybe I added 3/3.5lbs vs 4.5 lbs. Wasn't sure if you would see that via pressure reading.

Next time I clean the grids I'll have a better scale to be more exact.

 

[HermanTX]

Perfect - Thanks!

It's pretty tough to get the DE amount exact so maybe I added 3/3.5lbs vs 4.5 lbs. Wasn't sure if you would see that via pressure reading.

Next time I clean the grids I'll have a better scale to be more exact.

Just a couple of other items for a DE filter
When you check pressure of the filter - ensure the pump is at the same speed of your previous check. Pressure will vary with pump speed so always ensure things are equal.
If you backwash your DE filter, only add 80% of the recommended amount of DE for a completely clean filter. A backwash will never remove 100% of the old DE, so if you continue to add the full amount it will overload the filter grids.

 

[Barkyman]

Thanks. I had a rip in two fins and the PB gave me a brand new manifold with all new fins. So everything was basically brand new when I added the DE - likely a little light but better than too much. Good point on the 80% after backwash.