Overnight Water Loss w/pump off

[George D]

Yes, the one on the suction side had some old Teflon tape. The other plug had an o-ring. I turned off the pump for the night about an hour ago and no loss of prime. The housing looked like there were no signs of damage.
I probably should have left the plugs alone since the pump was not losing prime and there were no leaks around the pump.

Next is the plug test. Is the skimmer closest to the pump the one that has the line going to the pump?

 

[JamesW]

Both skimmers go to the pump. They either tie together underground or both go to the pump.

Plug one with a regular plug and the other with a plug that has a 1/8" hole.

 

[George D]

Completed the plug test with the leak detection dye. The dye was not sucked in by the small opening in the plug. Instead of a regular plug and screw a 1/8" hole in it I used a return with a slat and adjusted it so the opening is 1/8".
The dye actually rose towards the top.

When I adjusted the valve to skimmers only and then main drain only, the pump lost prime both times and I can hear the system make a sound like a air slowly leaking from the pipes. This does not happen at 50/50 skimmers and MD.
Is this the problem?

So the pump does not lose Prime and there are no signs of leaking at the skimmers. What else could it be?

 

[JamesW]

The dye test is tricky to get right. I wouldn't consider it to be definitive.

Was the pump lid off while doing the dye test?

You can try plugging all of the lines to see what difference that makes.

If it's not the skimmers, I would suspect that it's the main drain.

You can plug just the skimmers or just the main drain and check for water loss overnight.

You can do the dye test on the main drain.

The pump lid has to be off when doing the dye test or the overnight loss test with the skimmers or main drain plugged.

You could also do a pressure test of all lines.

That's where you plug the lines and pressurize them to about 10 to 15 psi for a few minutes to an hour to see if the pressure holds.

 

[George D]

Yes, the pump lid was off during the dye test. When you say plug all the lines do you mean skimmers, main drain and the returns?
How do I plug the main drain?
To test the main drain do I need to swim to the bottom and add the dye right on top of the MD?

Does the pump stay on during the pressure test?

Any idea why my pump loses prime when the valve is 100% at skimmers and MD but does not lose prime when valve is at 50% skimmers, 50% main drain? I can hear the air coming out of the pipes when the valve is at skimmers only and MD only.
Thanks.

 

[Thorvald]

Do you keep your pool warm? As a first year owner with a first time heater I am loving keeping it around 90 degrees when we want to swim. The only issue with this is that the cool night results in a lot of evaporation happening.

I also thought I had a leak due to the amount I would lose in a day or two but if the pool sat and the temp got down to ambient, problem went away.

Just one more thing to check.

—

I had a main drain hose leak on mine from the construction. What they did to find it was turn everything off, plug all lines at the pool and then run a compressor into each line. Then simple walked around listening for “hiss”. Sure enough they found it pretty quick (spike from concrete form for decking went right through the hose and was buried).

Cheers

 

[mas985]

Any idea why my pump loses prime when the valve is 100% at skimmers and MD but does not lose prime when valve is at 50% skimmers, 50% main drain? I can hear the air coming out of the pipes when the valve is at skimmers only and MD only.

When you isolate the suction line to one or the other line, the suction head loss increases and the pressure inside the pump basket decreases so the seals need to be much better with those valve settings.

The drain plug could be one source of the leak so you might want to find a gasket for that.

But where are you hearing air coming through? If you see it coming into the pump basket from the pipe inlet, then the leak is further up stream.

 

[JamesW]

I suspect that you're probably going to need to have someone pressure test the plumbing.

 

[George D]

Thanks for the explanation on the skimmers and MD.
If the drain plug is the source of the leak, wouldn't there be water on my garage floor or at least I would see the water dripping?

I only heard the air from what I believe were the pipes between the skimmer/main drain and the pump. I will reseal them also. Is water resistant caulk or silicone a good option?

How do I go about putting a plug in the main drain?

If all else fails, I'll take the advice and call a pool pro to pressure test the plumbing.

 

[JamesW]

I suspect that the main drain has a leak where the suction holds in water while the pump is on 50/50 but loses water when the pump is off and gains air when set to main drain only.

I think that the skimmer line might have a smaller leak where it loses only minimal water while off, gains air while on 100% skimmer and is neutral while set to 50/50.

I think that there might also be an above ground air leak.

 

[mas985]

If the drain plug is the source of the leak, wouldn't there be water on my garage floor or at least I would see the water dripping?

I wasn't implying the drain plug was the same leak where you were losing water. Air leaks and the water leaks could very well be at separate locations. I just assumed that since you have a very large air leak since you messed with the drain plugs, that is the likely source of at least the air leak. Also, if the drain plug is leaking air in, it may not leak water out because the differential pressures are different with the pump on vs off.

 

[George D]

I turned the pump off, dove down to the main drain and added dye near the drain and the dye did not get sucked into the MD. Is that the right way to do the MD test? The pump does not lose prime. I called for a leak detection expert to check the problem. Is there anything else I can do before they arrive? Thanks for your help.

 

[George D]

I called a leak detection company that locates leaks only...no repairs and the tech said with the pump running, turn the valve to 100% main drain and 100% skimmers. When on MD, there were a few bubbles in the pump basket and hissing sound from the pipe connections near the valve. When I turned the valve to 100% skimmers, there were many bubbles in the pump basket and bubbles coming out of the returns. Looks like a leak in the skimmer area and a small one by the md.

Should I still have him come and verify exact location of the leaks or should I call a company that repairs leaks also. I need to get back to him by later today to cancel if not necessary.
Thanks.

 

[mknauss]

hissing sound from the pipe connections near the valve.

Could that be your entire leak? Try running water over that area from a hose with the pump on. See if that clears the bubbles in the suction.

I would delay the leak detection company if it is possible your leak in your above ground plumbing. You may just need to rebuild a valve or repair a pipe connection.

Take care.

 

[mas985]

When on MD, there were a few bubbles in the pump basket and hissing sound from the pipe connections near the valve. When I turned the valve to 100% skimmers, there were many bubbles in the pump basket and bubbles coming out of the returns.

What is the filter pressure in both valve positions?

The hissing could indicate the valve is not sealing well. When in the skimmer position, did you hear the same hissing sound? If so, the air could be coming from the valve. When you isolate suction lines, the suction in the line gets higher and can draw in air through the valve only when you isolate the suction lines but not when both are on.

 

[George D]

There was a hissing sound when I turned the valve all the way to the skimmers also. The hissing occurs only when the pump is off. I forgot to mention that. If there is a hissing sound with the pump on, I am unable to hear it.
With the pump on and skimmers 100%, there are many bubbles under the pump lid and the returns. There are a few bubbles under pump lid and returns when valve is on MD only.
The pressure at 50% skimmers and MD is between 17 and 19. Same pressure when on MD. When on skimmers only, the pressure used to drop to 14-15 but right now it dropped from 19 to 17.
I didn't understand Mr Knauss suggestion. Do you want me to run hose water into the skimmers or over the pump lid and valve connections?
If my leak is in the above ground plumbing, shouldn't I lose water while the pump is on? I only lose water when the pump is off.

 

[JamesW]

I suspect that you have multiple suction side air leaks. Probably one on the main drain and skimmer lines under ground and probably at least one above ground.

You're going to need to pressure test the lines.

 

[mas985]

If my leak is in the above ground plumbing, shouldn't I lose water while the pump is on? I only lose water when the pump is off.

Not always. As I think I explained before the pressure between the outside air and inside the plumbing is different when the pump is on vs off. When the pump is on, the suction will be much higher in the suction lines and more likely to leak air in than when it is off, especially with seals. Also, when the plumbing is above water level, when the pump is off, there is a slight suction in the line so more likely to leak air into the lines. Only the lines that are below water level would leak water out because there is a slightly pressure forcing the water outward.

 

[George D]

I have a leak detection pro scheduled for Monday. His company only finds leaks and does not repair them.
I think I should go ahead with the appointment and hire a company to do the difficult repairs and il do the easier ones myself, in the spring.
Thanks.

 

[George D]

The leak detection expert checked this morning and he ran a pressure test, checked both skimmers and he concluded the leak is not from the skimmers. During the pressure test, the PSI remained at 10.
He noticed there is a thumb plug missing from the top of the Jandy valve that near the pump. He thinks air may be leaking out while the pump is off. He also gave me 2 #10 size plugs to place on the skimmers and to check if I still lose water.
He said that if it's a main drain leak, it could be a pipe connected to the main drain that's near the pump. He said once I open the pool in the spring to verify the water level.