Troubleshooting intermittent low pump basket water issue ...

[DeanP66]

I recently installed a Circupool RJ-45 SWG and have been having a strange issue. I have my VSP set to run 24/7 with two overlapping programs at 1100 RPM's. I leave my SWG on 24/7 as well and run it at around 30%. I'm still playing with the percentage until I get it dialed in. When I come out the next day to check on the equipment, I find that the water in the pump basket has dropped by about 3 inches. It seems to be running ok with no air bubbles and it's generating chlorine, but it's just low compared to where it was after priming pump and letting the program take over.

I recently installed the same SWG at my friend's house as well after I did mine and it seems to be doing the exact same thing. I plumbed both equipment pads from scratch within the last 2 years and was very meticulous with all the cutting and gluing, making sure I made square cuts, camphored the ends of the pipe, and also used purple primer and glue for all the pipes and fittings.

Any idea what's happening in the pump basket?

 

[duraleigh]

It's a common issue with a VS pump run on lower speeds. Mas985 has a good explanation for it which I don't quite understand but suffice to say what you are seeing is normal.

 

[kefjens]

I have a two speed pump and a SWG that has the same issue (but a different brand from yours). Twice a day I run the pump on high for 5 minutes to bleed out the air in the pump.

 

[DeanP66]

I was hoping it was something like that. Funny thing is that I don't remember it doing that before I installed both SWG's on each system.

 

[Jimrahbe]

Dean,

I think when the pump is running 24/7 at a low RPM, even a very small air leak will accumulate under the pump basket over time. Not sure why, but as my filter gets a little dirty the amount of air seems to increase.. Not by much, but noticeable...

I played with this one day, just as an experiment. I noticed that I could see very tiny bubbles come from around the lid gasket and collect in the top of the lid. Not a lot, or very often, but if you paid attention you could see them.

I installed a new lid and cam assembly, lubed and replaced the gasket.. Made zero difference.. It appears to me that when the pump is running, the vacuum under the lid pulls the lid down and makes the seal tighter. When the pump runs at a lower RPM, the vacuum is not as great and the seal is less air tight.

I recommend that you schedule your pump to run at an increased speed a couple of times a day, if it worries you.

Thanks,

Jim R.

 

[DeanP66]

Jim R, that's good advice. Thanks, I'll run a priming cycle for 15 minutes or so.

 

[mas985]

There are two reasons for air accumulation on low speed.

Air leak is one reason for air accumulation. Pump baskets will generally seal better with higher suction but only up to a point where the seal can no longer hold the suction. When run at lower RPMs, the suction decreases and the chance for leaking increases. It depends on the pump lid seal design.

Another reason for air accumulation is out-gassing. An IG pump is usually installed above water level and will experience low pressure in the pump basket when running. Dissolved air (O2, N2, CO2) will come out of solution when pressure drops. So when the flow is very slow, you can see tiny campaign size bubbles accumulating on the pump basket. Over time these will grow to a large size pocket of air in the pump basket. However, on higher speeds, you won't see the bubbles because the higher flow rate is enough to take them out of the pump basket through the return side where they dissolve again.

Generally out-gassing occurs all the time while an air leak may or may not be occurring. The way to tell the difference is the time frame. With just out-gassing, it would take many hours of run time to accumulate a decent sized air pock while an air leak will usually occur in less than a few hours. Sometimes though it may be hard to tell the difference.