Pentair Variable Speed Pump losing prime at lower speeds

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R

rdelisa

Bronze Supporter
Sep 16, 2017
78
Arvada
I have my Pentair variable speed intelliflow pump programmed to drop down to 1,150 RPM at night. This morning I noticed the pump was still running even though the pump basket was no longer full of water. Is this bad on the pump or is there enough water to keep it safe running this way? It is my understanding that the Pentair will shut off automatically if the pump is dry.

I have absolutely no signs of water leaking in any of my plumbing. Yet, there must be some air leaking somewhere, right? I used to be able to shut my old, pump completely off at night and it would remain primed. Singe I got the Pentair I've never been able to do this.

Also, my pump is an extremely long distance from the pool - a good 80 feet or so. This setup has been rather hard on pumps and it is extremely difficult to prime on startup. What would be an appropriate way to troubleshoot this?
 
r,

You said it.. your old pump held a prime overnight and your new one does not... That sounds like an air leak to me..

Could be many places, but I suspect they installed your new pump without pump unions and that the air leak is at the threaded portion of the input pipe.

Post a pic of your pump showing all the input valves and plumbing.

Here is a u-tube troubleshooting video... Find an air leak in your swimming pool. - YouTube

Thanks,

Jim R.
 
Getting air in the strainer basket at lower speeds often happens as pressure is lower then.

Fill the strainer basket with water on high speed. Turn off the pump. If the bubble returns, then there is an air leak. If it only happens when running on low speed, it is a common thing for variable speed pumps. More info in this thread on your pump type:

Pentair Intellilflow Variable Speed Pump Priming Problem

To troubleshoot your distanced pump, maybe go for smaller pipes. Or you go for a stronger motor, but check if filtration does not suffer from that.
 
Thanks for the video. This reminded me how the inside of my pump used to look before there was air. Now I have a couple of bubbles on top while pump is running even at high RPM. I did not notice any visible leakage using the water technique of the video. Could the air be caused by the SWG not being sealed properly? I am half-thinking, now, that this problem really started before I got the new pump, about the time the SWG was installed 4 years ago. I've been living with this problem for a while. Pump Installation.jpg

Jimrahbe said:
r,

You said it.. your old pump held a prime overnight and your new one does not... That sounds like an air leak to me..

Could be many places, but I suspect they installed your new pump without pump unions and that the air leak is at the threaded portion of the input pipe.

Post a pic of your pump showing all the input valves and plumbing.

Here is a u-tube troubleshooting video... Find an air leak in your swimming pool. - YouTube

Thanks,

Jim R.
Click to expand...
 
r,

Your SWCG is on the pressure side and is much more likely to cause a water leak than an air leak..

The most likely place for an air leak is..

1. Pump lid O-Ring,
2. threaded pipe at pump input.
3. O-Ring in side those unions (which are not pump unions)
4. O-Rings inside the Jandy Valve.

Thanks,

Jim R.
 
If your basket is full at high speeds, shut it off, does it stay full or do you see the water rushing out? If it rushes out, it’s an air leak. In addition to o rings and being lubed I would insure lid is sealed properly, filter has no air leaks at gauge or sight glass. I notice the screw in fitting, that might be your culprit too. Undo the Union and add two to three layers of Teflon tape or plumbers gunk to the threads.
 
r,

This is one of those situations were there is no good answer.. Due to your set up (no room between the pump and the valve) it would be a lot of work to try to replace what you have with pump unions and there would be no guarantee that it would make any difference...

Pump unions have an O-ring on the threaded end that goes into the pump and look like this.... Pump Union, Threaded 2 Slip - CPVC I'm just using this website to show a good pic.....

I would follow Pool_Medics advice and open the unions you have and inspect the internal O-rings they have.. I would unscrew the pipe into the front of the pump and reinstall it using pipe dope.

As a test, you can add Saran wrap around the plumbing and see if you can identify the leaking area...

The reason that I often ask for pics is to see plumbing like yours .. If you had all kinds of room between your valve and your pump it would make sense to install pump unions, but in your case, it would not be my first choice..

Thanks,

Jim R.
 
I turned the pump off overnight and this morning the pump basket was still full of water and looked exactly the same with just two small bubbles on the very top. It seems just with me tightening some things up helped because it has never held water before. When I powered it back on however, it went into priming mode. Im not sure if that is because the pump sensor sensed lower water or if it is just automatically priming upon startup. My SWG has trouble detecting flow when its first powered on even at fairly high pump speeds. If I am still getting a small bit of air I am almost certain it is the union fitting right before the pump. That was an immediate problem when plumber first installed and I had to tighten it up myself. I am very tempted to remove, check and or replace O rings and apply pipe dope and refasten. Just afraid I might make it worse!;)
 
Your Intelliflo has a priming cycle each time it starts. You can adjust the RPM it uses, the length of the cycle, or even turn it off using the keypad.
 

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R,

I would leave it alone and run it for a few days and see if the problem comes back... I suspect you have fixed it..

As Marty says your pump will automatically prime if it has been shut off..

As far as the SWCG goes, does the flow light not turn on right away or are you worried about the flashing red and green lights... When the IC40 first turns on, it goes through a calibration cycle that can last a few minutes... during this cal cycle, the salt light will flash red and green...

Thanks,

Jim R.
 
Thanks, Jim. The SWG light goes from red to green (Off to On) a few times, then eventually just stays off until I up the speed. This morning it was not able to maintain a flow at 1800RPM. I increased the speed to 2,000RPM then ran it for about 20 minutes. I went back to it and was able to lower it to 1600RPM and still works. Maybe I just didn't leave it on long enough.

Is there any harm to the SWG unit by having it on when the flow is low and the light is red?
 
R,

No harm as long as the pump is running....

What you describe sounds like a dirty filter... I suspect that if you backwash your sand filter, the SWCG will work again at your normal speed...

Thanks,

Jim R.
 
Thanks. You're right about the dirty filter. I badly need to clean and backwash. I've held off doing that as I simultaneously have been killing off a bad algae attack and messing with the pump issues since pool opening. Wanted to get the water cleared and settled so I could vacuum.
Pool now finally is holding chlorine and I can just about see the bottom, so it's about time.


Jimrahbe said:
R,

No harm as long as the pump is running....

What you describe sounds like a dirty filter... I suspect that if you backwash your sand filter, the SWCG will work again at your normal speed...

Thanks,

Jim R.
Click to expand...
 
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