Possible Suction Side Leak

Turbo1Ton

Gold Supporter
Dec 26, 2019
528
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Alright, I think I'm fighting a suction leak and I'm looking for any opinion/guidance to make sure that I'm not overlooking something simple, or that I haven't missed anything. This has been an ongoing issue that I have been trying to find for about 6 months, so nothing extremely new after the recent polar vortex*.

Issue is with my filter pump. I can open up my leaf cannister and pump, fill with water and start-up, and can purge all of the air out of the system. The priming speed will get most of it, but since I have an IFCS, there is quite a bit trapped in the zone valves that takes a little while to push through. I run my IFCS system @3200rpm. Then, when the system slows to 1600rpm, which is where I run the rest of the time, for SWCG operation, the water level in the pump basket will drop. Next day, when the IFCS kicks on, rpms increase and it will fill the basket, but it aerates the water, and I get tons of air coming through the lines. One thing to mention is I ran my pump @ 3200rpm during the entire 2 weeks of freezing weather we just went through and I had just one or two small air bubbles in the lid, no aeration to mention and no air bubbles through the return, so it appears to only happen when the rpms reduce.

*I will say that my spa suction line began to freeze up a few days in to the 2 weeks of freezing temps and when freeze protection tried to shift to spa, my pump went into priming mode and was mostly starved for a few minutes. This happened several times, while I was sorting things out as to what was going on. Not sure if any damage was done to the pump due to that, but it seems that the drop in water level is more significant since that event. It also appears that there is more aeration in the pump basket when it is full, than there used to be. Here's a video of what it looks like @ 3200rpm.

Pool was built a year ago, so equipment is all just over 1 year old. I reworked my pressure side plumbing from how my PB had installed it, but haven't touched the suction plumbing. I have examined and lubed the leaf cannister and pump lid o-rings several times with no luck. I've checked and lubed the drain plug o-ring, and the pump union o-rings. My next step is going to be opening up all of the diverter valves and examining the o-rings for them. I had not done this yet as I struggled to believe that a diverter valve that was less than 1 year old could have messed up o-rings. But that is the only thing I can think to look at next.

Am I crazy to think that the pump basket shouldn't lose water at all? My water features pump runs @1200rpm and stayed completely full all through last summer, through several opening and closing of the lid, to clean the strainer basket. I winterized my water features so I have not yet fired that system up this year to see how it is doing.

Is there something on the pressure side that could be sucking air? Generally I wouldn't think so, everything I know about hydraulics would say no, as pressure side leaks generally spray fluid, but thought maybe I'm missing something there.

Thanks,

--Jeff
 

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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
24,888
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
It is normal for a VS pump at low RPMs to develop an air bubble in the pump basket. If the pump basket stays full when running at 2000+ rpm I would not worry about it.
 

Turbo1Ton

Gold Supporter
Dec 26, 2019
528
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Ok. So I am still fighting this. I understand the air bubble in the pump basket, the ones right up against the lid, but my water level is draining down to almost half full in the pump basket. I am having to vent my filter daily. Kick it up to high speed, and it will churn bubbles like mad in the pump basket. Small bubbles, not the larger ones that sit right under the lid. And of course blowing bubbles like crazy out the returns and the skimmer venturis. And not the SWCG champagne bubbles either. Big ol' "dear Lord what just fell in the pool?" kinda bubbles, at times.

Two weekends ago, I built a smoke tester to pressurize the pump and suction side of the system, and did that. Similar to what they use when testing for automotive vacuum leaks. Found a fitting that would thread into the pump basket drain plug opening, and connected it up. No idea how much pressure I got on it but it was enough that I was bubbling back through my skimmer. Then I shut off the skimmer and main drain valves, with the smoke tester still connected, to see if any smoke came out of anywhere. No visible smoke coming out of any valves, pipe joints, unions, pump lids, nothing.

When I disconnected everything and put it all back together, I thought possibly it was some trash, or hair or something on the lid o-ring, as it filled and primed and there were none of the small bubbles churning in the basket. After my IFCS quit running for the day, and the pump speed returned to lower rpm, the pump basket was full, with the aforementioned bubble up against the lid. I thought for sure whatever it was that was causing the issue was corrected. But the next day when I went out, there was air in the system again. Blowing air out the returns, and I could hear gurgling water in the filter itself. Water level in the pump had dropped to just below the top of the skimmer basket.

I am at a loss as to what to look for next. I thought about swapping pumps with my features pump, since they are identical, and see if it goes away. At least that would tell me it was something to do with the pump, and not any of the valves, etc.

My previous post mentions I am running low speed @ 1600rpm. This was to overcome the losses in the heater to keep the SWCG flow switch happy. When I added the heater bypass, I am now able to turn it down to 700rpm and keep the switch happy. But I am running @ 1000rpm as a safe buffer.

Could the system be too open to where the pump, at that low of a speed/flow, can't keep the piping full? Is that a thing? I don't know. My water features sure don't have that issue. I run them @ 1200rpm and never have any problem.

Hopefully what I have said makes sense. It does in my head. LOL! Please let me know if I am confusing things, or stuff isn't making sense.

--Jeff
 

Turbo1Ton

Gold Supporter
Dec 26, 2019
528
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Well, still having the issue. I just finished up pulling apart all of the diverter valves and checking the o-rings and such, and lubricating them all. Hope that will fix it but I'm not holding my breath. I can see a constant amount of tiny bubbles churning in the basket, even when it is completely full. My water features pump on the other hand has the occasional small bubble churn around, but nothing like the main pump. Next step is to swap the pumps between the two systems. I will do that next weekend if this weekends events didn't correct it.

Is there any way that it running low during the freeze, when my freeze protection was jacked and it let the spa suction start to freeze up, caused any issues? Could the pump seal have run dry for too long?

Super frustrated at the moment.

--Jeff
 

Turbo1Ton

Gold Supporter
Dec 26, 2019
528
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Ok, I closed everything up and restarted, went through the priming and the pump basket was full, with the normal amount of larger bubbles up against the lid. I was running @ 2700RPM to push the air through the system and through my IFCS. All air was pushed through. I turned the system down to 1000RPM and left it. About 20 minutes later, I remembered I forgot to clean my skimmers, so I bumped the speed back up to 2700 to pull the junk down into the skimmer baskets as I changed them, and was watching the pump when I kicked it up. When I did, we will call it an explosion, of smaller bubbles happened in the pump basket. I don't know what this means or if it is helpful for diagnosing but wanted to bring it up.

Thanks,

--Jeff
 

Turbo1Ton

Gold Supporter
Dec 26, 2019
528
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
This weekend I was able to swap the pumps between the water features and the filter systems. The issue stayed with the filter system, and did not move with the pump. So clearly the issue is within the suction piping, and not the pump.

Any suggestions as to what I need to be looking for? I've dismantled and re-lubricated all o-rings in the suction side. I've cleaned and lubricated all lid o-rings. I've flip flopped pumps and cleaned and lubed the pump union gaskets. I've injected pressurized smoke into the suction side of the system and was unable to find any leak points.

I am at a loss as to where to go next.

--Jeff
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
21,221
Bedford, TX
Jeff,

I have a rent house with a small DE filter.. If I let it get too dirty, that is exactly what my pump looks like. Filter pressure in only about 5 lbs. so it does not look like a dirty filter, but it is..

Not saying your filter is dirty, but rather something in your pressure side could also be the issue.

Just thought I'd make your life more complicated.. :)

Sorry,

Jim R.
 
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Bperry

Gold Supporter
Aug 20, 2020
252
Knoxville, TN
Pool Size
27000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-60
Can you isolate the IFCS and the filter to check if one of those is leaking?
 

PointeTaken

Bronze Supporter
Aug 28, 2019
129
Hoover, AL
Pool Size
12000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Turbo Cell (T-CELL-5)
This weekend I was able to swap the pumps between the water features and the filter systems. The issue stayed with the filter system, and did not move with the pump. So clearly the issue is within the suction piping, and not the pump.

Any suggestions as to what I need to be looking for? I've dismantled and re-lubricated all o-rings in the suction side. I've cleaned and lubricated all lid o-rings. I've flip flopped pumps and cleaned and lubed the pump union gaskets. I've injected pressurized smoke into the suction side of the system and was unable to find any leak points.

I am at a loss as to where to go next.

--Jeff
Since it’s Hail Mary time...are you by chance using a skimmer sock? If mine gets even the slightest bit soiled, it induces enough drag on the suction side that air builds up.
 

Turbo1Ton

Gold Supporter
Dec 26, 2019
528
NE Oklahoma
Pool Size
14500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Not saying your filter is dirty, but rather something in your pressure side could also be the issue.

Just thought I'd make your life more complicated.. :)
Great...:rolleyes:

Seriously though, that is helpful. I cleaned my filters last fall and have yet to do so this spring. Was planning on it here in a few weeks, even though the pressures are not up.

Can you isolate the IFCS and the filter to check if one of those is leaking?
I can isolate the IFCS, not the filter though. I have not paid a lot of attention to that, since I was expecting it to be a suction side problem. I will do a few trials switching the IFCS off and on and see what I get.

Since it’s Hail Mary time...are you by chance using a skimmer sock? If mine gets even the slightest bit soiled, it induces enough drag on the suction side that air builds up.
I do use hairnets, but I have used them from day 1. I will check again with them clean and see if I notice any difference.

--Jeff
 

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