Gradual High Filter Pressure Increase

[vancemac]

Hello everyone,

I have a problem with a gradual pressure increase in my DE filter and decrease in flow. After backflush (currently no DE in the system) the pressure starts out at 10-12psi and good flow to little over 30psi and significantly less flow over the course of 3 or 4 hours. This is repeatable because I can backflush (water is clean) and the pressure goes down initially again. The problem has come on gradually since last summer. The filter grids have been removed, cleaned and looks in good condition.

The pool and equipment is approx 4 years old and I have a Pentair FNS Plus DE Filter with a NSF valve attached.

Any suggestions are appreciated.

 

[JohnT]

How is your water chemistry? Anything less than sparkling clear water will behave like that with a DE filter.

Have you done a TSP soak and acid wash on the grids?

 

[duraleigh]

+1 what JohnT said. Your filter is doing it's job....filtering out stuff from your water and getting plugged up as a result. Your water chemistry will probably indicate you have or have had FC too low which has caused an algae bloom....whether you can see it or not.

 

[jblizzle]

Are you replacing the DE after each backwash? You should never run it without DE as the grids will clog up quickly, then requiring you to open up the filter and cleaning the grids .... Respect especially if you water is not clear.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[vancemac]

Thanks for the comments. I am going to remove the grids tomorrow and run the pump without them just to make sure that there is not a restriction some where else. If the pressure stays low, I'll know it is the grids and go from there. I didn't know that running it without DE would cause a problem so that may be the cause. I'll post the results.

 

[vancemac]

Hello all,

I did an acid wash on the grids and adjusted the pool chemistry (needed some stabilizer and acid) to get that back in-range. The grid went from a dingy yellow to almost white. The pressure was 10psi without the grid in the system and when I replaced the grid and charged with DE, the pressure only increased to 12psi and is holding. WOW what a little cleaning will do. Problem solved and I want to thank everyone with the help and comments.

Again, thanks for the information.

 

[jblizzle]

Nice work. Glad we could help.

Let's see how long it takes to get up to 15psi, where we would recommend you backwash and recharge the DE (with around 80% of the clean charge).

Posted from my Droid with Tapatalk ... sorry if my response is short