Hard time figuring out Suction Leak

[les_garten]

I have the setup as noted below in my sig. Bought the house in Apriland it had the leak when I bought it. I was worried and called out a "pool guy" and he said not to worry about it! Yeah, OK. I've been working on it ever since when I think of something to try.

I have a lot of air in my pump basket when set in the following settings

1) Cleaner Full on On it's own Suction run
2) Drains shut off
3) Skimmer line shut down about 2/3-3/4 to run cleaner.

I changed the seal on the Pump Lid, changed all the o-rings in the 2 way suction side valves for the skimmer, cleaner, and drain lines.

Then I listened with a stethoscope and thought I found the problem. The line coming into the skimmer on pipe-valve junction seemed to have an air leak. I cleaned up the pipe and applied a big bead of JB water Weld all around the juncture. Still leaking and I swear that valve still sounds funny.

I also listed to the drain stopcock on the pump volute and it's quiet. I listened all around with a stethoscope which caused me to start evaluation of the skimmer circuit. I was assuming it was the cleaner line before that, because I only saw the problem when I ran the cleaner. But In reality, I only see the problem when I close down the skimmer line valve to run the cleaner.

So I just did another experiment that is telling me something, I just don't know for sure what.

I took the cleaner loose from the wall of the pool so that the cleaner line will be unobstructed.

I made sure the drain was closed and the skimmer and cleaner valves are wide open. No leak basically and the cleaner and skimmer valves are quiet to listen to them.

I closed the cleaner valve about 3/4 like I normally close the skimmer valve when I run the cleaner. No leak, everything groovy.

I then opened the cleaner valve and closed the skimmer valve like I'm trying to run the cleaner and the air bubbles rush in.

I really don't want to replace the valve if that's not the problem, but I don't know where else it could be.

Anything else you folks can think of?

 

[JamesW]

My guess would be the threaded fitting going into the pump, the skimmer valve or the cleaner line. I would say to redo the fitting and the skimmer valve and pressure test the cleaner line.

It's also possible that the cleaner line might be clogged with debris, which would cause excessive vacuum and cause any weak seals to allow in air. In addition to pressure testing the cleaner line, you should try to make sure that it is clear.

If the pump gets really loud when the air bubbles start, then the pump might be cavitating as well as sucking in air. You could get a vacuum gauge to check the vacuum pressure when the air is getting in.

 

[les_garten]

If I run 100 % on the skimmer with the cleaner closed, no bubbles.
If I run 100% on the cleaner with the skimmer closed, no bubbles.

If the cleaner line is partially closed while the skimmer is open, no bubbles
If the skimmer line is partially closed while the cleaner is open, bubble city

Seems like it has to be in the skimmer line at the valve. If it was behind the valve somewhere, I think closing the valve would make it go away not come on?

Does that Logic make sense?

 

[JamesW]

It could be that the skimmer valve has some kind of defect that only happens when the skimmer is partly closed. Other than that, it does seem like a difficult leak to find. A picture of the equipment might be helpful.

 

[les_garten]

Here's some PIX, and a few extra I have questions about that are unrelated. I'll post them as Links, they are large.

http://www.turbonet.biz/misc/Pool/P1010765.JPG
http://www.turbonet.biz/misc/Pool/P1010766.JPG
http://www.turbonet.biz/misc/Pool/P1010789.JPG

The middle valve is the skimmer. It would be a PITA to replace. I would have to do all 3 valves it looks like.

What are these 2 Gadgets? I think one is a Vacuum breaker for the pool if someone is sucked onto the drain. The little skinny one I have no idea.

http://www.turbonet.biz/misc/Pool/P1010768.JPG
http://www.turbonet.biz/misc/Pool/P1010767.JPG

 

[JamesW]

I think that this picture shows a “tamper resistant atmospheric opening" for a Suction Limiting Vent System, which is most common in Florida.

Here is another one, also in Florida.

The Suction Limiting Vent System should be Teed into the main drain line (as shown below), so it shouldn't be opening if the main drain is closed, but it might be related. The vent system might also be Teed into the vacuum line because it is a submerged suction and would probably be required to also be vented.

http://www.poolspanews.com/2010/112/112svrs5.html

If possible, you might want to contact the pool builder to get a copy of the construction plans to see how the vent system was designed and installed. This should be documented in the plans and inspections.

Something looks wrong with the pipe connections to the pump. There is usually a male threaded adaptor that connects the PVC to the female threads of the pump. It looks like the pipe just goes directly into the pump without an adaptor.

http://www.doh.wa.gov/ehp/wr/guidance-s ... ndrain.pdf

 

[carlscan26]

What about replacing the seals in that valve?

 

[les_garten]

If possible, you might want to contact the pool builder to get a copy of the construction plans to see how the vent system was designed and installed. This should be documented in the plans and inspections.

Something looks wrong with the pipe connections to the pump. There is usually a male threaded adaptor that connects the PVC to the female threads of the pump. It looks like the pipe just goes directly into the pump without an adaptor.

I had tried the pool builder and he's out of business.

The line into the pump I believe is threaded. The one on the suction line had some epoxy put on it by the Pool Guy I had check it out during the pre sales inspections.

 

[les_garten]

What about replacing the seals in that valve?

Replaced all the seals in all the valves.

 

[duraleigh]

The one on the suction line had some epoxy put on it by the Pool Guy I had check it out during the pre sales inspections.

I am just giving it a WAG, but I would check that closely. Epoxy is not a very good material in that application and I can picture normal vibration breaking it loose.

 

[les_garten]

The one on the suction line had some epoxy put on it by the Pool Guy I had check it out during the pre sales inspections.

I am just giving it a WAG, but I would check that closely. Epoxy is not a very good material in that application and I can picture normal vibration breaking it loose.

I'll look that over. The pool guy putting it there as a guess, I watched him. Even when the epoxy was soft, it made no difference.

The reason why I think it can't be there is because the only thing that causes my problem is partially closing the skimmer line. Partially closing any other line does not do anything. When I had that valve apart for seal replacement, I didn't notice anything wrong with it. But I'm wondering if the body has a crack in it.

Perhaps I should shoot a video.

 

[Bama Rambler]

If you want to rule out the skimmer valve, I'd take a piece of plastic (i.e. plastic bag) and tape it around the pipe then tape the side closed and fill it with water above the valve, and run it in the position you know it leaks and see if it still leaks. It'll take a little playing with to get it to hold water but it's easier than replacing the valve.

 

[les_garten]

If you want to rule out the skimmer valve, I'd take a piece of plastic (i.e. plastic bag) and tape it around the pipe then tape the side closed and fill it with water above the valve, and run it in the position you know it leaks and see if it still leaks. It'll take a little playing with to get it to hold water but it's easier than replacing the valve.

That's a heck of an idea!

I had been thinking about wrapping it in plastic to try and air seal it, but wasn't sure I could choke it off enough. This is a much better idea! Thanx!

 

[carlscan26]

Wow Dave - great idea!

 

[linen]

Is it common to not have a unions on/near inlet and outlet of pumps? Just never saw that before, but I suppose that means less to go wrong/leak, but it also means if there is a problem (like at your epoxy covered joint at the inlet) you are cutting and later plastic welding again. I also wonder if having a union (and a slight amount of give associated with it) would reduce the stress on joints like that?

 

[les_garten]

Is it common to not have a unions on/near inlet and outlet of pumps? Just never saw that before, but I suppose that means less to go wrong/leak, but it also means if there is a problem (like at your epoxy covered joint at the inlet) you are cutting and later plastic welding again. I also wonder if having a union (and a slight amount of give associated with it) would reduce the stress on joints like that?

Common down here in the Sunny South. I've had a few houses with pools and never seen a union. But I always thought there should be unions, a lot of them.