Leak during pressure test - is this acceptable?

[greenwood207]

Hello! Looking for some help regarding expected PSI changes under a manifold.

We are building a new pool and in the plumbing stage. The plumbing is all in place (connected to filter/pump) and we passed the city inspection. One thing to note that prior to the inspection, we had a leak at the filter gauge that the PB came back to fix and after re-pressurizing, we found another leak in the O ring of the pump. On the third try, the PB pressurized right before the inspector came over and passed holding at 30 PSI for 10 mins. I had some concerns as I noticed the pressure had dropped from 30 to 26 overnight (3:00 PM, measured again 7:22 AM next day). I brought this up to the PB and he said this was expected as there is areas in the equipment that will naturally lose pressure (eg O ring, connections). Is this true? If so, how much can you expect to lose through the equipment?

I was not comfortable with the PB explanation and was afraid there was slow leak somewhere. The PB disconnected the pipes from equipment and created a manifold and pressurized to 32 PSI (11:11 AM). The PB said the pressure should remain the same with small changes expected from the skimmer (1-2 PSI) since the connection is threaded. Over the last 2 days, I noticed the PSI to change (table below)

Question to TBF folks (thank you!!): what PSI loss can I expect under a manifold? We are located in Southern California where the temperature is moderate (high 85, low 65). How much PSI loss is expected through the skimmer? Also through equipment?

SAT 7/9/22	12:47	32
SAT 7/9/22	17:58	32
SAT 7/9/22	22:30	30.5
SUN 7/10/22	8:24	29
SUN 7/10/22	10:13	29
SUN 7/10/22	14:59	29.5
SUN 7/10/22	21:24	29
MON 7/11/22	7:53	27

 

[AQUA~HOLICS]

1-2 psi max loss with a manifold. Did the plumber add water to the system to help show location of leaks if any prior to pressurizing ?
5 psi seems excessive in 3 days and true that the skimmer is most likely area for the leak but also look for a faucet bib threaded in the above ground lines. Spray soapy water on those two areas to confirm.

 

[PoolGate]

That is no problem at all.

 

[SoDel]

Were the lines pressurized with air or water? I’m no expert but having seen these tests done in a variety of contexts, if water is used, the slightest leak will cause a huge change almost immediately. Water is (essentially) incompressible so the only “spring” in the system is the flex in the pipe walls.

With air, it’s different. Enough spring in it where it will just drop slowly. If the leak is very tiny (perhaps inconsequential) it will drop very slowly.

 

[PoolGate]

Were the lines pressurized with air or water? I’m no expert but having seen these tests done in a variety of contexts, if water is used, the slightest leak will cause a huge change almost immediately. Water is (essentially) incompressible so the only “spring” in the system is the flex in the pipe walls.

With air, it’s different. Enough spring in it where it will just drop slowly. If the leak is very tiny (perhaps inconsequential) it will drop very slowly.

I've always seen these done with air.

 

[SoDel]

I've always seen these done with air.

Would you consider trying water or comparing the two methods on a job? Due to its incompressible nature, water is fast to detect even very small leaks. For high pressure testing, using water is also much safer (although for pool plumbing, not really a factor).

 

[PoolGate]

Would you consider trying water or comparing the two methods on a job? Due to its incompressible nature, water is fast to detect even very small leaks. For high pressure testing, using water is also much safer (although for pool plumbing, not really a factor).

I'm not sure how they would even use water. Seems it would be near impossible to fill the plumbing with water.

 

[AQUA~HOLICS]

The plumber will put some water in the manifold lines while building the system along with air and the loss of water will show location of breach.
Its added through the hose bib with a double female connection.

 

[PoolGate]

The plumber will put some water in the manifold lines while building the system along with air and the loss of water will show location of breach.
Its added through the hose bib with a double female connection.

If water goes in, air has to go out. How does that happen?

 

[SecoSteve]

Greenwood,

On our build in 2020, I had the same concerns. They would pressurize the system with air, and slowly but surely, each time they did this, the pressure DID in fact drop. It took a day or two, but it would always drop. I was assured it was normal. I know your feeling, but sometimes you have to trust the PB.

 

[AQUA~HOLICS]

Air gets pressurized inside the plumbing without going out.

 

[greenwood207]

Were the lines pressurized with air or water? I’m no expert but having seen these tests done in a variety of contexts, if water is used, the slightest leak will cause a huge change almost immediately. Water is (essentially) incompressible so the only “spring” in the system is the flex in the pipe walls.

With air, it’s different. Enough spring in it where it will just drop slowly. If the leak is very tiny (perhaps inconsequential) it will drop very slowly.

Thank you for the reply. The lines are pressurized with water. The PB did say that even with slightly leak, it would cause a change immediately however this was not the case in which we found a small leak in one of the spa lines but the pressure only dropped 32 to 28 over 1 day but held at 28. This leak was more of a dripping faucet too. So I guess it is not always the case that any small leak will show significant drop immediately.

The table above is the readings after the PB fixed the spa pipe leak and repressurized to 32.

 

[greenwood207]

1-2 psi max loss with a manifold. Did the plumber add water to the system to help show location of leaks if any prior to pressurizing ?
5 psi seems excessive in 3 days and true that the skimmer is most likely area for the leak but also look for a faucet bib threaded in the above ground lines. Spray soapy water on those two areas to confirm.

Hello! The PB added water to the system so it is pressurized with water. How much should I expect of PSI loss out of a skimmer? Is there then additive PSI changes expected with temperature change (highs 85, lows 65)?

There is no faucet bib out of the skimmer, they put a loop pipe (apologies if I am not using the correct terminology). The faucet bib is connected to the manifold which has the gauge attached.

 

[AQUA~HOLICS]

In reality no pressure loss from the skimmer should be noticed and if their is it’s an easy fix. The only pressure difference should be from the temperature changes due to the plumbing being exposed in the trenches. When their is a difference and no recovery that would also indicate a possible leak.
The plumbing system is designed to have no leaks at all, not even a single drip from glued joints or threaded cuplings.
The faucet is typically on the manifold only and not on the skimmer loop.

 

[SoDel]

If water goes in, air has to go out. How does that happen?

Plug the downhill end. Fill the pipe or piping system being tested with water on the uphill end. Attach the pressure tester and pressurize with water. Close valve and watch gauge. There will likely be a (very) small amount of air in the pipe but almost all water. There are other ways depending on what’s being tested but it’s doable. Water much better than air (IMHO).

 

[PoolGate]

Plug the downhill end. Fill the pipe or piping system being tested with water on the uphill end. Attach the pressure tester and pressurize with water. Close valve and watch gauge. There will likely be a (very) small amount of air in the pipe but almost all water. There are other ways depending on what’s being tested but it’s doable. Water much better than air (IMHO).

"End"? I have 7 returns and 3 drains in my pool. Not sure how you'd fill all that with water.

 

[SoDel]

Thank you for the reply. The lines are pressurized with water. The PB did say that even with slightly leak, it would cause a change immediately however this was not the case in which we found a small leak in one of the spa lines but the pressure only dropped 32 to 28 over 1 day but held at 28. This leak was more of a dripping faucet too. So I guess it is not always the case that any small leak will show significant drop immediately.

The table above is the readings after the PB fixed the spa pipe leak and repressurized to 32.

That’s odd. E.g. ASME B31.9 section 937.3 requires hydro test at 1.5x working pressure for ten minutes. Your pipe would pass with flying colors if part of a building (despite having a leak).

ASME B31.9-2020

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studylib.net

 

[SoDel]

"End"? I have 7 returns and 3 drains in my pool. Not sure how you'd fill all that with water.

You test the drains and returns at the same time? How do you do that?

 

[SoDel]

That’s odd. E.g. ASME B31.9 section 937.3 requires hydro test at 1.5x working pressure for ten minutes. Your pipe would pass with flying colors if part of a building (despite having a leak).

ASME B31.9-2020

Free essays, homework help, flashcards, research papers, book reports, term papers, history, science, politics

studylib.net

My pad is uphill the pool so the drains and skimmer lines would be one test. The returns a separate test.

 

[greenwood207]

That’s odd. E.g. ASME B31.9 section 937.3 requires hydro test at 1.5x working pressure for ten minutes. Your pipe would pass with flying colors if part of a building (despite having a leak).

ASME B31.9-2020

Free essays, homework help, flashcards, research papers, book reports, term papers, history, science, politics

studylib.net

Hi SoDel, you are correct. we had passed the plumbing inspection -- the PB had pressurized the system 15 minutes before inspector arrived and it held at 30 PSI for 10 minutes. We have had several moving parts to address any PSI declines so the PB put in a manifold to eliminate any sources. Under the manifold, we've seen a decline from 32 PSI to 27 over 3 days. Hope this clarifies.