Pump basket almost never fills

Underwhere

Well-known member
Jun 5, 2017
68
Manchester NH
I've struggled with the plumbing for years. Literally years.

I have a small in-ground pool. 12k gallons.
I put in a 22ST filter with Zeosand a few years ago. It is oversized yes.
And I just recently put in a Pentair Variable speed pump. 1.5HP. Oversized yes.
I have 2 returns and a skimmer. No main drain. Everything on 1.5" lines.

I believe I have minor leak(s) somewhere in the pool lines as I get bubbles almost constantly and have for several years. I currently have a trench dug around the pool so I can replace these lines but have not done so yet. I will. I have someone who is supposed to come up to do the lines but his schedule is full for the near term.

In the meantime the wife wants the pool open so I am struggling to get by and I understand this is really just duct-tape fixes at the moment...but I appreciate any assistance in troubleshooting an imperfect system for the time being.

I have used foam soap over all connections at the pump and filter and have not found any leaks at all above ground.

The info I have:
1. I have figured out through trial and error that 1950rpm is a sweet spot where the pump basket fills without air. The filter sits at around 6PSI at this time.
2. Above the 1950rpm the pump basket fills and then it surges and the basket water level drops. This cycle happens over and over again. Almost like the pump primes, hits an air bubble and loses it, then primes again. I'm not sure what's going on. I don't think I have a large enough leak anywhere to cause this.
3. A few times at 3000RPM at initial priming the pump basket has completely filled with no air bubbles. The filter pressure spiked to about 15psi at this time. It was glorious and lasted about 15 seconds and then the basket water level dropped.
4. Trying to vacuum is frustrating. If I connect a vacuum I can feel the suction at the skimmer. I can hear the pump basket fill and lower with my ear and that manifests itself in the vacuum working then not working every minute or so. Very frustrating.

My thoughts:
Since my pump and filter are oversized I was wondering if I am trying to draw too much water through my 1.5" pipes? I was thinking of putting valves as regulators between pump and filter, and between filter and returns to try and increase the backpressure on the system and hopefully keep the basket full. Thoughts?
 

1Sammy

In The Industry
Jul 20, 2017
371
Windsor, Ontario. Canada
As you know your problem is air getting in the suction line. Can be a break someplace, are you sure there is enough water in the skimmer so it don't suck low and take on air. When you set up your vacuum, does it go in the suction line at the bottom of the skimmer ?
 

Underwhere

Well-known member
Jun 5, 2017
68
Manchester NH
Are you getting a vortex in the skimmer? How high is the water level?
No vortex in the skimmer. The water level is just about halfway but even when it was much higher, closer to the top of the skimmer when I first opened the pool it was still doing the same thing.

As you know your problem is air getting in the suction line. Can be a break someplace, are you sure there is enough water in the skimmer so it don't suck low and take on air. When you set up your vacuum, does it go in the suction line at the bottom of the skimmer ?
I will double check the water levels to make sure it's not sucking air in. I don't think it is. I'll take a video.

As far as vacuum - I am screwing in a fitting into the suction side of the skimmer and attaching a hose directly to it.
 

Underwhere

Well-known member
Jun 5, 2017
68
Manchester NH
The video showing the basket filling perfectly during startup at 3000 rpm and then suddenly drops pressure for some reason. I did not touch anything.


The skimmer:

The return jet:
 
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1Sammy

In The Industry
Jul 20, 2017
371
Windsor, Ontario. Canada
I can not see being overpowered as your problem. The air is getting sucked in someplace between the basket and the pool. My guess on your vacuum issue is a hole in the hose. Overpower would collapse that hose.
 

jtpipkin

Bronze Supporter
Oct 2, 2016
247
albany, ga
shot in the dark here, but I'm struggling to see how it could prime so well and then just lose it. Have you lubed the O-Ring on the pump lid - really well? possible inspect or replace?
 

Underwhere

Well-known member
Jun 5, 2017
68
Manchester NH
shot in the dark here, but I'm struggling to see how it could prime so well and then just lose it. Have you lubed the O-Ring on the pump lid - really well? possible inspect or replace?
Yeah I can't figure out the prime and loss either. No change in pump RPM.

Yes I have some pool o-ring lubricant that I used. Cleaned off the flat surface with my fingers and made sure there was no dirt or sediment.

The lid was very tight...i almost through that I had somehow mis-threaded it but it just seems to be a very tight lid.
 
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Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
19,094
Bedford, TX
Under,

It is pretty clear looking at the videos that the pump is running out of water.. this is not because the pump is too big or that your lines are only 1.5"...

Something is not letting the water get to the pump. Either your weir door is sticking or you have a clog in your suction line..

If this were my pool, I would make sure that the water level is at the middle of the skimmer.. Then I would hold the weir door down (Put a brick on it) and then see how your pump works..

If that does not help, I would use a Drain King to run water backwards from the pump into the skimmer... The idea being to blow anything in the line back into the skimmer..

Thanks,

Jim R.
 

Underwhere

Well-known member
Jun 5, 2017
68
Manchester NH
Under,

It is pretty clear looking at the videos that the pump is running out of water.. this is not because the pump is too big or that your lines are only 1.5"...

Something is not letting the water get to the pump. Either your weir door is sticking or you have a clog in your suction line..

If this were my pool, I would make sure that the water level is at the middle of the skimmer.. Then I would hold the weir door down (Put a brick on it) and then see how your pump works..

If that does not help, I would use a Drain King to run water backwards from the pump into the skimmer... The idea being to blow anything in the line back into the skimmer..

Thanks,

Jim R.
Ok thanks Jim.
The water is exactly in the middle of the skimmer right now.
I'll hold the weird door down.

I have not tried the Drain King. I should. When I place my hand around the skimmer I do feel quite a bit of suction. Do you think it could still be clogged?
(I just ordered the 1.5" drain king right now)
 
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Underwhere

Well-known member
Jun 5, 2017
68
Manchester NH
Another interesting note:
If I try and fill the basket with my hose before priming it never completely fills past the bottom of the suction line. Water goes into the suction side and I hear the pipe starting to fill...but it just never seems to fill up all the way.

Another problem? Indicative of a major leak because I don't lose a ton of water.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
19,094
Bedford, TX
If I try and fill the basket with my hose before priming it never completely fills past the bottom of the suction line. Water goes into the suction side and I hear the pipe starting to fill...but it just never seems to fill up all the way.
under,

That is something called "Gravity"... :mrgreen:

As you try to fill the pump basket, the water simply flows back into the pool through the skimmer... It will always happen if your pad is above your pool water level.

Since you can feel strong suction at the skimmer pipe, that does not sound like your pipe is clogged.. But, it seems to be intermittent, so who knows.. Troubleshooting is just eliminating things until you get lucky...

Basically, if things are working well, your pump can't suck more water out of the skimmer, than can fall in from the pool..

Another thing to try would be to by-pass the filter and see what happens...

Thanks,

Jim R.
 

Underwhere

Well-known member
Jun 5, 2017
68
Manchester NH
Funny thing. I looked this morning and my pump basket is full and no air bubbles are coming out of my returns.

I didn't change anything.

It did rain yesterday and the temps are lower. I wonder if that's affecting any leaks that I have.
 

Underwhere

Well-known member
Jun 5, 2017
68
Manchester NH
So I tried something new.
I put in a valve on the returns. I was messing with the valve to increase the pressure at the filter (which normally sits below 5psi)
I closed up the valve so that the pressure at the filter sat at 10-12psi.

And for 2 days straight there do not seem to be any bubbles in the basket, none coming out of the returns.
All of this at 1950RPM.

I'm not sure exactly what this means...but this seems to be the sweet spot for me. I'm hesitant to touch anything for the time being.
 

1Sammy

In The Industry
Jul 20, 2017
371
Windsor, Ontario. Canada
What you have done is block the output of your pump and adding more pressure to your filter, reducing the flow into the pool. That in turn has slowed the suction going into the pump. So now with the reduced movement of the water it is not picking up the air from wherever your problem is.