Air in pump pot

Hello,

I have client who has a challenger pump that always has a bubble of air in the pump pot. The pool does not lose any water nor is there any water in the pump area or around the pool. There was a leak on the return to the spa, but it was fixed. The pool has one drain, two skimmers, and a spa drain. I can turn off the skimmers and the bubble somewhat goes away. I can turn off the drain and its worse. Any ideas on how to track down a above ground air leak? Maybe its underground. Not sure. But I am 100% positive the pool doesn't lose water. Sometimes I have to drain water out of the pool because its a cart filter.

Sometimes the flow isn't enough to clear that bubble. Are there bubbles coming out the returns indicating a continuous injection of air on the suction side? If no, then ignore the bubble if it's small and not causing pumping problems. Air could have gotten in through the skimmer if the flow in the skimmer forms a vortex. Sometimes this will momentarily cause a little air to get in. If it is indeed an air leak in the plumbing it could be so small that water doesn't leak out and may only leak under a slight vacuum. If it is a joint problem then smearing a little silicone seal around the joints while the pump is running should cure it. While running, the silicone will get sucked into the leak before it cures. If you suspect a bigger leak then a stethescope may help using the open tube to sniff the joints but since you don't see water leaking the leak may be too small to hear it.
Hope this helps.
Al

Luke, burning the midnight oil, eh? This must be bothering you to keep you up so late - I know the feeling :) .
From your description of the 'symptoms', I'd say the first place to look is the skimmers (as the bubble lessens when they're closed and gets worse when it's the only line pulling). I assume that the two skimmers are tied together. Do you have pressure testing apparatus? , I'd pressure test the skimmers - if it's an above ground leak, you should be able to see water 'weeping' out where the line is bad, and the test will tell you if the line is compromised. As another question, is the plumbing 'black poly'? :eek:
Actually, the first thing to check is if you can see bubbles comming into the pump? The first thing to do is make sure that the lid gasket is well lubed and in properly and that the drain plugs aren't pulling air (as Al said, a small leak won't drip but under a vacuum will draw air). If you see air comming into the pump with the MD off, you can direct a dribble of water over any suspect connections (the pump lid, any glued connections, the plugs, the VALVE, any threaded connections), if the bubbles start to disappear - you've found A leak! (though sometimes there's more than 1)
Please keep us informed as to your progress and/ or any further questions on this - Good Luck with it!