PSI dropped after filter plumbing replaced - is this expected?

Annorax

Active member
Jul 10, 2015
32
MA, USA
Hi all,

I have an aging in ground, vinyl lined, DE filtered pool. I recently had some maintenance work done on it:

- Liner replaced
- Leak in underground suction line at nylon corner fitting cut and repaired
- Above ground plumbing around filter was very old and replaced - a new valve to control which line (or both) to suction from, chlorinator, piping, etc...

Now that the pool is filled with water again, everything seems OK but one thing I notice is that the PSI on the filter went from about 18-19 to about 14-15. It still seems to suction fine (there are 2 suction lines, the skimmer and the regular line that was repaired) and the filter basket has a few air bubbles but no more than normal.

Is this expected?
 

duraleigh

Admin
Mod Squad
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Platinum Supporter
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In The Industry
Apr 1, 2007
34,251
Sebring, Florida
Sure. You have improved the system resulting in less resistance and more flow probably. Do the returns feel a bit stronger? Perfectly normal.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
18,752
Bedford, TX
Ann,

Most people don't realize that in most cases, lower filter pressure is better than higher filter pressure.. Filter pressure is not how great your pump is doing, but rather how much effort it takes for the pump to push water through the filter... The lower the pressure the easier the pump can push water through the filter..

As long as you have good strong flow out of your pool return lines, then it is a Win - Win..

Thanks,

Jim R.
 

Annorax

Active member
Jul 10, 2015
32
MA, USA
Thank you both for the helpful feedback, this is good to know.

One other observation I'm seeing after all of these changes - when running the pump seems fine, there are some air bubbles when first starting it but within a minute or 2 they are gone. After stopping the pump, even before all of this I saw a little bit of air bubbles in the filter basket, but now I think I am seeing more. It takes maybe 20-30 minutes after stopping the filter and then I see some air bubbles coming in from the suction input to the filter basket. Within about 45-60min there is maybe 1-2 inches of air in the basket, though the filter is still primed as I can start it up and within a brief period the air is gone. The first thing I made sure was the basket lid was tight and it is.

I don't think this is normal and I'm hoping there is nothing wrong underground again. What do you guys think? I'm still experimenting with the valve (I can turn it off, choose either the skimmer or the suction line, or 1/2 on both) but it's slow going. I have it OFF now and will want to see if I see air bubbles. If I still do I would think either the valve is broken or the new pipe from the valve to the filter basket has a leak? Though the fact that it takes a while for the air bubbles to show makes me think it is a potential leak further away.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
18,752
Bedford, TX
Ann,

In theory, when you turn the pump off, no air should leak into the pump basket.

The first thing I would do is make sure the o-ring under the pump lid is well lubed..

In the big picture, as long as when you turn on the pump again the next day, the pump quickly primes and you don't have a huge gush of bubbles and noise coming out of your pool return lines, it is not a big deal.

Please help us under stand your pool and equipment by completing your pool's signature.. Settings and then Signature. You can use my signature as an example.

Thanks,

Jim R.
 

Annorax

Active member
Jul 10, 2015
32
MA, USA
Thank you for the feedback. I've added some details to my signature and made an album: My Pool

With the valve in the OFF position, I still see air bubbles coming in (again, it takes about 20-30 minutes after stopping the pump), though I can't tell if it's coming from the pipe into the basket or from right above the basket where the lid fits in. The gasket looks good (the gasket is inset in the basket itself and not the lid). I haven't lubed the lid gasket in a while - would something like vaseline work? I don't see any leaks coming from the basket with the filter on though so could it still be leaking from the basket?
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
18,752
Bedford, TX
Ann,

Much harder to seal flex style pipe than it is PVC.. The "square" cell on the Superflo pump is also harder to seal...

Unless the pump won't prime the next day, I would not screw with it..

Thanks,

Jim R.
 

Annorax

Active member
Jul 10, 2015
32
MA, USA
Hi Jim - I'm a little confused. I thought you said I should lube the gasket on the pump box? I don't think I have a Superflo pump. The one I have looks identical to this but older. The gasket is underneath the lid. Is it OK to lube that with vaseline?


EDIT

I just Google'd around a bit and it says vaseline is NOT good for rubber and should not be used as a lube. It says it's better to get a silicone or teflon based lube.
 
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