Leak Detection

[stephen11962]

10' x 40' x 4.5' deep vinyl lined pool. Loses, in full summer, 1" per day when the water is above the skimmers. When the water drops below the skimmer the loss is about 1/2" per day. I have read elsewhere that, on average, 1/2" loss per day is due to evaporation. So, it seems that there might be two locations of leaks. In addition, I have seen a water blister on one side of the pool between the steel pool side and the liner. That side is the side where the pool plumbing is located. The blister seems to dissipate when the pump is running. Today, the pump has been off for 2 days and I cannot see the blister.

I have tried locating leaks via dye in critical locations (skimmmers, lights, main drain, etc) and can not find any area where the dye seems to carried away by a leak. This includes the skimmers, one of which has 'surface cracks' in the horizontal lower plane. It seems to be a surface blemish.

Today, I tried pressure testing the skimmer piping and ended up frustrated because I cannot isolate the skimmer loop. The main drain and the skimmers are connected to the pump via a Jandy 3-way valve. Turning the valve to skimmers only seems to almost isolate the loop. When I pressurize the loop and go to the pump I can hear water escape. The noise diminishes as the pressure diminishes. The Jandy valve is hard-plumbed to the piping. There are no union disconnects, so I cannot plug any of the lines. (Is this a "mistake" of installation?) If this were high season and the water was warmer I could try plugging the main drains, not an easy task even when warm and a pool only 4.5' deep.

I am now waiting to see how low the water will go.

All this to ask if anyone has something I am not seeing and can lead me to success?

Stephen

 

[gwegan]

Some information about your pool and location would be good. Pictures would be even better. Have you done the bucket test to determine what your actual loss is?

Generally plumbing doesn't leak its the connections of the plumbing to the pool that leak. If you are in a metro area a leak detection company can be well worth the money.

So let the pool drain down to just below the returns. I would check all the returns into the pool.

 

[stephen11962]

Location is the east end of Long Island, NY. Not a major metropolitan area, but a lot of pools.

The pool leaks 1" water per day when the water level is above the skimmers. Now, the water level is below the skimmers. I daily measure the level of the water below the bottom of the skimmer. I now read a 1/4" loss of water per day for two days in row with levels starting at -1 1/8" below bottom of skimmer (prior days are inaccurate due to rain). All evidence seems to indicate that the leak is above the present level of the water.

I have used dye to try to locate leaks with pump off, via piping from the skimmers and the main drains, from the lights, and the various connection points of those things to the liner. None of these tests indicated any hint of water loss and I was very careful to make sure that water was still with no movement.

But I have to go back to the fact that water loss occurs (according to my log) with the water above the skimmers, meaning that the leak is there. That is why I wanted to test the skimmer piping but was frustrated by the seeming 'leak' at the Jandy valve. What I do not understand is that the skimmer piping is subject to low pressure when the pump is on and a leak is unlikely from this piping when the pump is on. But the dye test was negative. And, the later level is below the skimmer lips now and the pump is off yet there is about 3-4" of water at the bottom of the skimmer wells. If the leak is in that piping that water should drain out. AND, there is that blister between the liner and the pool wall that appears when the pump is on.

I think I understand the logic of leak detection yet the evidence that I have confounds me. I hope someone can throw some light on this. Sorry for all the words.

I do have one 'easy' question about initial installation practices: Should there not be unions at each pool device (talking about the Jandy valve here) that facilitates servicing? My Jandy valve is hard-plumbed.

Stephen

 

[pooldv]

It is a best practice to use unions for the pump, filter, swg, heater or other equipment for easier servicing/removal. But, often that doesn't happen. Also, often the replacement equipment doesn't fit in the same footprint and requires replumbing anyway.

Jandy valves are serviceable without removing them so are always hard plumbed.

 

[gwegan]

I would concentrate your efforts at the pool skimmer interface. I might even get new gaskets and the skimmer installation manual and re install the skimmers so you know that connection is correct. That is the most likely source of your problem and is consistent with your described symptoms.

 

[stephen11962]

It is a best practice to use unions for the pump, filter, swg, heater or other equipment for easier servicing/removal. But, often that doesn't happen. Also, often the replacement equipment doesn't fit in the same footprint and requires replumbing anyway.

Jandy valves are serviceable without removing them so are always hard plumbed.

Thanks for the info. The installer is not on my 'good' list. Original piping limited access to the heater and there were no unions on the filter piping except for pump removal.

Stephen

 

[stephen11962]

I would concentrate your efforts at the pool skimmer interface. I might even get new gaskets and the skimmer installation manual and re install the skimmers so you know that connection is correct. That is the most likely source of your problem and is consistent with your described symptoms.

I think I will go with your suggestion after monitoring levels for a couple of more days. BUT I still wonder about the blister on the side of the pool. I can't see how the skimmer problem would induce this. Where the blister appears is not near the skimmers. Puzzling!

Thanks

Stephen

 

[stephen11962]

Back again. Recapitulating:
Water above skimmers, pool looses on average 1" water per day.
Water below skimmers, pool looses on average 1/4" per day. I assume this is expected.
Water level in skimmer wells (main drain selected for suction lines) almost no loss on daily basis.
From the above I conclude that there is no leaking from the piping.

I did make a pressure stick and used it to check the piping of the return (jets) piping. There is a pressure drop, from 30psi to 10 psi in 15 hours. (I attribute this to slight leaks in the pressure stick and/or plugs used to block other openings in the pipe. The amount of water in the pipe is inconsequential compared to the amount of water in a 1" loss in 24 hours.)

So, the culprit has to be "pool skimmer interface" as mentioned by gwegan.

BUT there was the 'blister' on the side of the pool. The location of said blister in not near the skimmers. I assumed before that it occurred from leaks in the return piping because the blister is on the side of the pool where the piping is.

I have already tried to check out the skimmer interface but am stymied by not being able to remove the cover of skimmer, Hayward. We have a black vinyl cover and the black plastic cover "seems" to be a snap on cover that covers up the clamping ring (white). I might be reluctant to use too much force, but the cover is not snapping off easily. Any one have insights on this problem? And the blister?

Thanks for the help

Stephen