Sand Filter PSI question- new pump a little disappointing

[mas985]

I just saw the additional information.

Is the suction side 1.5" plumbing a single line from the pool to pad or from each skimmer/main drain?

One other question is do you see air in the pump basket?

Pump noise is the other indicator of issues.

[simsjim]

Hey Mark

Thanks for the observations and questions.

To answer your questions-

-The pump is significantly quieter than the previous pump. It does not sound (smell or feel) like it's working hard at all.
-1.5" pvc plumbing all around
-2 skimmers are combinded into one line near the pool (I dont like this- but its under the concrete deckin, so tough to modify)
and main drain has its own line. - so its two intake lines controlled by a pentair three-way valve at the pad.
-There appears to be a small bit of air in the pump (If you are familiar with the Pentair basket-pot window, the air pocket is about the size of one of the 'pie slices'.) Do you think I am gettting air in through an underground or above ground union on the suction side?

Additonal info: My completely blocking either the skimmer or the main intake via the pentair valve had no appearant impact motor noise, air in the basket, or PSI.

I may try to pressure test the suction end. What would a DIY need to perform this test? If not possible, what would a ball-park cost in NE US be for a pro to come out and perform the test?

Again - thanks for the tips!

[CarlD]

My pump at low speed typically runs at 5psi.

Have you checked the obvious--is your sand filter completely full with 325# of sand? When my filter was installed, the bozos were putting in 150# of sand and I caught them and made them add the extra 50# because it is a 200# filter. Too little sand is not good. Are you sure they used filter sand and not sand-blast sand (which is cheaper)?

Also a lateral in the filter could have been damaged by the installer--if sand gets in the pool, that's a clear sign.

I almost think you should empty your filter and install 325# of filter sand yourself, see if that fixes it. Watch the sales: Filter sand can be had for $5 for 50#--$35 to replace your sand.

If the sand is OK, you can also use Pocono's DE trick to both better your filtering AND increase your pressure. It's cheap and those of us who use it think it works really well.

Also, as your filter sand ages, it should get dirtier and increase pressure--and filter better.

Just some ideas to check. I sure lots of folks have other ideas, too

[mas985]

I would have expected the PSI to drop if you closed off the skimmer or main drain. It sounds as though maybe your new filter PSI guage is not working properly. This is a fairly common problem although not so much for new filters.

Just to confirm, you did not see PSI change with either main drain or skimmer but did you set the valve for both main drain and skimmer on? Any change there? Have you checked to see if there is any blockage in the lines. You can backflush the lines with a hose and a rag (to seal) or get yourself a Drainking.

Also, about how high is the pad above the pool? Although this does not add to the total head loss, elevation will increase the suction head and decrease the return head relative to no elevation.

1.5" plumbing is really too small for the suction side and could be primary cause to the air in basket and low PSI reading. Even though you new pump is only 3/4 HP, it is still a very strong pump and possibly too strong for your plumbing. The pump cannot draw enough water so it is drawing air through the seals in the pump lid or valves. A larger pump would only make this worse so don't go that route. However, a two speed pump would allow you to run at the low speed most of the time which your plumbing could easily handle.

If you want to go to the trouble of measuring the suction on the pump, you just need a vacuum guage, Sears has one for $20, and get an adapter so that it can screw into the pump's drain plug at the bottom of the basket. But this will only confirm that your suction head is very high and not really tell you why.