Pump losing prime, taking in air but can't find source

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R

rosariom

0
Jun 1, 2013
17
New Jersey
Hi everyone

Hopefully someone can help me because I'm about to call in a dump truck and fill in my pool (not really). I think I'm taking in air. The pump starts up, makes a humming sound like it's priming and then starts working. Within 10 seconds, it loses prime and starts humming again... about 30 seconds to a minute later it starts working again and then the same thing, it loses it. I should mention that I had the same issue with a Hayward pump that I just replaced with a Pentair 2HP and replaced pretty much all the suction-side PVC and Jandy valve. I've tried switching the valve from skimmer to main drain but I still have the issue, so I don't think it's under ground (unless both the skimmer and main drain lines have a leak. Since It's not just a few bubble but the pump losing suction I assume it's a pretty big leak, in which case wouldn't I be losing a LOT of water? How would I go about figuring out if I have an underground leak?

I should also mention that besides a skimmer I have another round cover that doesn't have a skimmer basket. When the pump isn't working, that fills up. When it's working, water comes from the sides and drains down the bottom. The most anyone has been able to tell me about it is that is has to do with the main drain.

I read somewhere else that it could be caused by a clog somewhere in the line and to try to use a drainking to clear it, but this has been happening since last year and I blew out the lines. Wouldn't that push out any debris in the system?

I'm now at a complete loss as to where to go from here. Does anyone have any suggestions?

I forgot to mention that when it loses prime, the pressure goes to 0.
 
More than likely the unknown basket is some kind of anti-entrapment device for the main drain. That is a potential source for your problem.

What happens in the pool skimmer while this process is going on?

Are you trying to run on only the skimmer or drain, or both at the same time? A 2HP pump needs a lot of water, and potentially could be too much for your plumbing.
 
The skimmer stops taking in water, the returns stop as well and the whole system pretty much comes to a halt. The pump makes a horrible humming sound that makes me feel like I'm putting too much strain on it.

I've tried both at the same time, and one at a time and the same situation happens.

I was running fine with the 2hp Haward pump for about 2 1/2 years I lived here and I believe it was never replaced since 1995. Maybe the Pentair is too much for the system, but I find it strange that both had the same symptoms. The Hayward has a leak under it and the bearings went so that's why I replaced it thinking there was some kind of leak in the pump and it was taking in air.

Now I'm really worried that the leak could be underground.

Thanks
 
So after playing around with it some more and trying to clear the lines with a DrainKing, I discovered that it looks like my problem is the main drain and not the skimmer. If I put it on skimmer it's perfect now. Moves water like it used to. I guess when I was testing with just the skimmer I didn't wait long enough or possibly the DrainKing cleared a clog. I have a three way Jandy valve as if I switch the main drain slightly on, I start getting air. If I open the main drain completely that's when the pump gets so much air it loses it's prime.

Now here's the interesting thing. When I realized it was the main drain, I stuck the DrainKing in that other opening that is tied to the main drain, I put the DrainKing in the hole that feeds from the main drain at the bottom of the pool. I stupidly had the DrainKing half in the hole and it quickly filled up and popped! I would think there would be less pressure pushing water out the main drain at the bottom of the pool than popping the DrainKing bladder.

So now I suspect my problem is between the drain at the bottom of the pool and that hole on the side. So here's the million dollar question. How do I clear that out? Do I have to put on my dive suit and get in there? Or so I call in the pool company and have them blow it out?

Thanks for your help!
 
I have a three way Jandy Valve that has the main and skimmer feed into the pump so I can turn off either the skimmer or the main drain.

There's only one port in the skimmer housing but next to the skimmer housing there is a round cover and what looks like another skimmer, but it looks like it's for the main drain. There is a hold on the side that seems to feed from the bottom drain, then there is another hole that feeds from the side of the pool. At the bottom of this housing there is a hole that feeds to the pump. I know because I was testing with the drainking to see where the water ended up.

From what I can tell, the water isn't coming from the bottom drain fast enough for the pump so that main drain housing and emptying and allowing air to get into the system. When that happens, the pump loses prime and that housing starts filling up. Because there is a hole on the side of the pool into this housing, it never overflows, but until the pump starts up again, it everything stays this way. When the pump finally starts again, the whole process starts over again.

Since it was working perfectly fine about a year and a half ago, I believe the issue is between the bottom drain and the hole on the side of that drain housing. like I said if water was flowing freely, I don't think the DrainKing bladder would have burst, but I'm not sure.

One other thing I should mention. Last year and the prior years, I had pool companies open and close my pool, with horrible results. In fact, I think this issue started when the guy I hired last year opened my pool. I say this because there used to be two jandy valves (one for the main drain and one for the skimmer) and it's possible that the people the used to open my pool never opened the main drain all the way, possibly putting additional strain on my pump which resulted in my having to replace it.

Sorry if this isn't clear, It's hard to describe. Hopefully the diagram will help.
 
Okay, I think I understand. There's another skimmer lid but it doesn't have a skimmer. It just has a well with two holes in the bottom. One to the main drain, one to the pump via the three-way valve.

If that is correct, it sounds like you're missing the diverter. You're just sucking the water out of that well faster than it can flow back in. Look around for something like this
lovingHDTV-SkimmerDiverter.jpg
or
joenj-SkimmerDrainDiverter.jpg
 

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Quick update in case anyone is interested. Thanks to Richard's suggestion, I went through some pool equipment in an old shed and found an out of place return jet fitting. the hole back to the pump is threaded so I was able to attach that (basically cutting the flow back to the pump) and now everything is working as normal!

Thanks again Richard for your suggestion!
 
I re read this and cant understand it. Just trying to learn something new.

I also have a jandy valve, one is going to the skimmer and another going to the main pool drain.

The skimmer has 2 holes, one of which is going to the jandy valve and the other is pluged/unusable.
 
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