Strange leak in my friend's pool - also need help identifying equipment / piping

[JoeFletch]

I'm trying to help a friend locate a leak in his pool but we are really struggling to find it and wanted to see if anyone can assist remotely.

A few things to note that are causing concern.

• The pool looses about 4" worth of water a week. Not sure how many gallons that is, but I suspect it is really high.
• Every time the pump starts, there is a significant amount of air that is pushed out of the pipes and into the pool.

Troubleshooting / observations.

• There is no air in the pump basket strainer. So I do not think that there is an issue in the pipe(s) from the pool to the pump.
• We tried to isolate the 4 pump discharge legs and ran into a couple of problems.
  • The manual values did not close all the way and did not want to force them and break them.
  • Each leg that was partially isolated resulted in air coming out of the other pipes in the pool.
• The ground was dug up as much as possible (for today) in an attempt to get to the first fitting. No visible leaks.

With all of this being said I suspect that the leak is in the pipe from the discharge of the pump to the pool. But we are struggling to pinpoint the location of the leak. Any suggestions are welcome!

Pool equipment setup and layout.


Pump inlet pipes; return from pool / skimmer (I'm not sure which is which) and then return from spa.


Return / supply to pool; Popups, waterfall, main jet / side wall and then spa.


Popup cleaner container. Check valve - not sure what this check valve is for. I was thinking that this is for the pool overflow but we cannot locate the overflow port in the pool. So not sure what this check valve is for. Another possibility is that it could be a check valve going to the popup cleaners but I am just guessing at this point.


Not sure what the vertical tee is for.


Another tee.


There is also this pipe U in the ground by the equipment pad. While the pump is running, I do not feel any water flow through this pipe. I have no idea what this is for!

 

[ajw22]

Working backwards from your pics...

I think the U is a Hartford Loop to keep water from getting up the air blower pipe.

The vertical T looks like a spa bubbler air intake.

Dunno about the CV. You can open the CV and blow air into the lines and see where bubbles come out.

No idea about the leak. At some point you need leak test equipment like the pros use...

Anderson Manufacturing Company, Inc.

: Helping The Pool Professional Solve Leak Problems

www.leaktools.com

 

[JamesW]

The Ts are probably suction limiting vents, which is mostly a Florida thing.

The check valve probably goes to the Spa.

You should be able to see the flapper move when water is flowing through the check valve.

 

[JoeFletch]

I think the U is a Hartford Loop to keep water from getting up the air blower pipe.

I found a picture in this post to visualize it.

I think the U is a Hartford Loop to keep water from getting up the air blower pipe.

The vertical T looks like a spa bubbler air intake.

So what is the difference between a blower and a bubbler air intake?

Dunno about the CV. You can open the CV and blow air into the lines and see where bubbles come out.

Good call on the check valve. Problem is hooking something up with enough pressure to overcome the pressure from the pool water. Although once you take the cap off, I suspect that water would flow out if it is lower than the pool level.

No idea about the leak. At some point you need leak test equipment like the pros use...

Anderson Manufacturing Company, Inc.

: Helping The Pool Professional Solve Leak Problems

www.leaktools.com

Do home owners typically buy equipment like this? Are home leaks that common in order to justify the costs of the equipment?

 

[JoeFletch]

The Ts are probably suction limiting vents, which is mostly a Florida thing.

I found this...

FREQUENTLY ASKED QUESTIONS ABOUT THE FEDERAL POOL & SPA SAFETY ACT
Question 12: What is a suction limiting vent system?
Answer: Suction-Limiting Vent System -- a pipe vented to the atmosphere that connects to the suction pipe between the pool and the pump. When a high vacuum event occurs, air from the vent pipe replaces the water in the suction pipe thereby breaking the suction. The vent opening is protected by a tamper resistant cover.

The check valve probably goes to the Spa.

You should be able to see the flapper move when water is flowing through the check valve.

Now that you mention it, I have a spa check valve on my pool but it is in a different location.

 

[JoeFletch]

Long story short, turns out that there was a leak at the skimmer. My friend was using the wrong testing dye and was showing a false-negative at the skimmer. He had to hire someone to find it and repair it.