Sudden problem with dedicated suction line

[nabril15]

Hello
I recently had my pool resurfaced, and the issue happened right after that; I don't think the resurface is he culprit, but I mention it in case it has a bearing in the issue.
I have 3 valves (the big blue ones) that control my suction: main drain, skimmer, and dedicated pool cleaner used for the Hayward navigator. Since the resurface job, the pool cleaner line barely sucks any water; using the clear plastic measurer, it barely dips and doesn't even reach the top MIN line, and the pump's basket barely fills up. Even using 1 hose segment the suction is minimal and the pump's basket barely fills. The other 2 suction options (main drain and skimmer) suck fine with full power. If I attach the hose to the skimmer's hole, it suctions fine; I removed the hose segments 1 by 1 to see if one of them is broken, but I never lost suction. Therefore, the hose segments are fine.

Common sense says that perhaps my blue valve is letting air in perhaps?? I poured water with soap on it to see if i saw bubbles, but I didn't see any. What else can I try?

Thank you

 

[mas985]

Even using 1 hose segment the suction is minimal and the pump's basket barely fills.

Does this happen only when using the cleaner line? Does it happen with the skimmer and MD open?

With all three lines open, are you still seeing air in the pump basket? There should be none.

 

[nabril15]

Does this happen only when using the cleaner line? Does it happen with the skimmer and MD open?
With all three lines open, are you still seeing air in the pump basket? There should be none.

Thank you MAS985
I correct my initial statement that the basket barely fills; it fills 1/4.

I tested your scenario with all 3 lines open and the basket is full and there are no bubbles coming out of the return lines.
I unscrewed the suction line adapter from the wall and only left that valve open - perfect suction with the basket full and no bubbles from the return lines. If I connect 2 hose segments to it, the bubbles return immediately. Therefore, there's obviously an issue with the hoses, right? Even though they are submerged most of the time.

 

[mas985]

Well, maybe. Suction side leaks are hard to find when dealing with a suction side cleaner. The problem is that with the cleaner on and the other suction ports off, the suction increases in all parts of the plumbing which means that a leak that did not exist before may start leaking under higher suction.

unscrewed the suction line adapter from the wall and only left that valve open - perfect suction with the basket full and no bubbles from the return lines.

Under this scenario, was the skimmer and MD off?

If so, then the leak could still be anywhere in the suction line. Is there any way to force the hoses fully underwater and keep them there? If the bubbles go away, then yes it is probably the hose. If they do not go away, then it is probably another part of the suction line.

Another test is to shut off the cleaner and MD lines and use the skimmer with the same test as you did before with the hose. If there are no air bubbles in the pump basket then it probably isn't the hose because it should leak with the skimmer connection too.

 

[nabril15]

Another test is to shut off the cleaner and MD lines and use the skimmer with the same test as you did before with the hose. If there are no air bubbles in the pump basket then it probably isn't the hose because it should leak with the skimmer connection too.

thanks again Mas.....Last week, I did use the skimmer suction line and attached the hoses to the skimmer's hole. The suction worked well though I saw a small amount of bubbles (more than normal) coming out of the returns.

Yes, in my scenario that I unscrewed the adapter the MD and skimmer lines were turned off. I agree with your suggestion about keeping the hoses underwater, and I already did that. Last week, I tested all of this by attaching 1 hose to the return line and definitely keeping it underwater since the suction line is about a foot below the water line. Even with 1 hose segment completely submerged, the bubbles were plenty and the basket was 1/4 full.
Somehow it seems that unscrewing the adapter makes the difference??? Although, I find it hard to believe that is the culprit.

 

[mas985]

The adapter is probably causing higher head loss and suction which is making something else leak.

 

[nabril15]

The adapter is probably causing higher head loss and suction which is making something else leak.

Mas--the frustration continues. I attached 4 segments of hose, with the navigator at the end, directly to the suction hole WITHOUT the screw-on adapter, and the bubbles and suction decrease happened INSTANTLY. All 4 hose segments were completely submerged.

I've also noticed that my water is decreasing faster than normal. Perhaps, I have a combination of things.

 

[mas985]

So that would indicate the leak is somewhere else. Either in the pipe itself so somewhere near the pad. I would take a look at the valves first since they are easy to get to.

But the higher than normal water loss is also a concern. If confirmed, it could mean that the leak is indeed in the pipe somewhere. I would do a bucket test to confirm the leak. Do the test with the pump running and then again, with the pump off.

 

[nabril15]

I write with my problem fixed. A professional leak tester determined the problem to be something that I had when I bought the house. The wall fitting of the suction line that is threaded to acccept the screw-in coupling was not glued by the resurfacing folks. They left it loose, and a small amount of water leaked out of that area somehow. After sealing the inside with epoxy, the auction returned to normal and the water level remains the same. This was remedied the same way when I first bought the house, but I failed to mention it to the resurfacing company.

Thank you to everyone and happy 2018