Leak in new water lines

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SMC_55

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Hello all! Long time reader first time poster.

I can not locate the leak. I have installed and plumbed a new bathroom complete with tub, shower and double vanities with sinks.

I have all the water lines installed with PEX and copper crimp rings and attempted to do a pressure test with air. I have installed a 120 psi pressure gauge and a Schrader valve to charge the system. I have charged the system to 50 psi numerous times finding a few leaks. The leaks have always been at the threaded fittings that have Teflon tape. I took them apart, cleaned off all the tape and reinstalled using blue monster pipe thread sealer. In every case this has fixed that particular leak. I have also been testing all the joints with Oatey leak detector fluid. I have tested every joint, I have tested every fitting and I still have a leak somewhere because it starts to lose pressure immediately.

After going thru the system probably 3 times completely testing every fitting and every joint and I cannot locate the leak!!

Someone out here please help with any ideas you might have. I have also heard talk about testing with dye and a black light. Anyone have any experience with this method with water lines. Is it safe?

Desperate1

Thanks for your time!!
 

Reach4

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I think you need a set of longer wrenches. Yours are too stubby. Longer lets you apply more torque.

Also, it could help to use better tape, rather than the cheapest.

So in the leak locating topic, can you isolate the leak by closing valves? That could help you isolate cold from hot.

Have you closed the stop valves for sinks and toilets?

Have you tested your crimps with a go no-go gauge?

How about turning on the city water, and look for the puddle?
 
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Kreemoweet

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SMC_55 said:
...it starts to lose pressure immediately.

An air test will always do that. When air is compressed, it heats up. Sending it into a metal pipe system will cool it off rather rapidly,
which causes the air to lose pressure.
 

Mr tee

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Make sure the leak isn't somewhere on your test gauge, I fell for that one once.
 

SMC_55

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Thanks everyone for your input.

Reach4....i thought over tightening could cause a leak also. Fine line between tight and over tight I guess.
This is a complete add on system to current and is not hooked up to existing system yet. Was trying to avoid the water test and making a mess of things.
Cold side is capped with a sharkbite fitting (tested this also no apparent leak) and the hot side has a schrader valve and test gauge on it. (Tested this also no leaks). Cold and hot sides are connected thru the hot/cold diverter in the shower with no cartridge installed yet. Diverters have test plugs installed. All the shutoffs are not installed yet and lines are all capped.
Thanks again for your input!

Themp & Jeff Young - water is currently not hooked up yet was trying to test with air first and avoid water so far. Thank you

Kreemoweet - complete PEX system - thank you

Mr Tee - I've tested everywhere on the gauge.....no leaks detected - thank you
 

Reach4

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Reach4....i thought over tightening could cause a leak also. Fine line between tight and over tight I guess.
If you are using 1/2 inch pipe thread or bigger, and 10 inch wrenches and are moderately strong or 6 inch wrenches and are very strong, I doubt you can cause a leak on metal to metal by hand. I could be wrong. If using plastic male threads and metal female female, some care is needed. Use plastic-safe pipe dope and maybe also good PTFE tape. If the wrenching is awkward, you will not be able to apply as much torque.

If screwing into plastic female threads, I am not sure how to describe (or even know) how tight to tighten, but use plastic-safe pipe dope and good ptfe tape. I like the Oatey pink or yellow "gas" tape. Yellow is not just for gas. If it leaks, give it another 1/8 turn.

For metal compression threads, lubricate the ferrule/olive with pipe dope or plumbing grease. Again, if you have a leak, give it another 1/8 turn, and don't worry that you will be crushing 3/8 od copper tubing.

I am not a plumber. A plumber would have a better feel for what is enough.

For the air, kreemoweet makes a good point.

Cheaper go-nogo gauge:
sharkbite-pipe-tube-crimpers-23080-64_145.jpg
Probably not the source of your problem, but that should be routine with crimp pex.
 

SMC_55

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Reach4....I am using PEX 1/2 inch brass adapter with male thread into Delta rough in valves with female thread. These fittings and my shower head elbow and my hand held elbow all check good since I redid them with pipe thread seal.

All my PEX crimps have been check with a go/no go gauge as I installed them and they all checked "go"!

I don't know what else could possibly be leaking. That is why I asked if anyone has had any experience with the diagnostic dyes and a black light and using it in water lines.

Thanks again guys!
 

Jeff H Young

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it can be frustrating could be a valve can be a leak in the pipe away from a joint a slit or something . it goes from 50psi to zero in how long?
 

SMC_55

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I have never actually timed but the lower it gets the slower it gets. But I would say probably 10 - 12 hours and it is all the way depressurized.

Yes very frustrating indeed!
 

Jeff H Young

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I have never actually timed but the lower it gets the slower it gets. But I would say probably 10 - 12 hours and it is all the way depressurized.

Yes very frustrating indeed!

Ok well that's nothing to do with the temp. in the house being hot or cold. I usually use real soapy water from dawn d/w detergent in spray bottle. another guy showed me a better way to find real small leaks. I take a small cup and put I'm going to guess 1 part soap 3 parts water and with an acid brush or small paint brush whip it up to a good lather and brush all the joints. Im a little cautious to recommend how much airpressure . it can be dangerous I've blown a 2 inch cap thru drywall and twisted damaging a stud . I believe more air the better.
Hopefully your new bathroom is not tied into the system and is totally isolated (I dont mean just a valve turned off ) and system is capped and not connected to new.
Cant you run a hose out to the meter or neighbors house or something?
 

SMC_55

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From previous post....

This is a complete add on system to current and is not hooked up to existing system yet. Was trying to avoid the water test and making a mess of things.
Cold side is capped with a sharkbite fitting (tested this also no apparent leak) and the hot side has a schrader valve and test gauge on it. (Tested this also no leaks). Cold and hot sides are connected thru the hot/cold diverter in the shower with no cartridge installed yet. Diverters have test plugs installed. All the shutoffs are not installed yet and lines are all capped.
 

Reach4

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Ultrasonic leak detector would be the good deal for finding a small air leak.

Measuring time to zero is hard. Measuring the time to drop from say 50 to 40 could be more useful to describe the leak. Do you have a test procedure that you must meet?

Do you know about preconditioning pex for an air pressure test?
 

SMC_55

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I will try to measure time from 50 to 40.....no certain test procedure....just no leaks is all im after....this is my bathroom....do not know about conditioning pex for air test.....1st i heard of it.

Thanks
 

Jeff H Young

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PEX isnt ridgid it will expand definitely read up on it. it stretches causing drop in pressure . I knew that but completely forgot about it I wouldn't think it would drop to zero though.
Reach 4 thats a good heads up what might be a problem with his test!
 

SMC_55

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Measured pressure drop using stop watch on my phone.

50 to 45 PSI - 3.0 minutes
50 to 40 PSA - 6 minutes 22 seconds - (+3 min 22 secs)
50 to 35 PSI - 10 minutes 11 seconds - (+ 3 mins 49 secs)
50 to 30 PSI - 15.0 minutes - (+4 mins 49 secs)

each 5 PSI that it dropped it got slower

As far as conditioning pex for air test.....all I have found was bringing it to 120 PSI for a short period of time then dropping it to 80 PSI for a certain period of time. Is this the preconditioning you are referring to? If not could you please explain?

Thank you!!!
 

Reach4

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As far as conditioning pex for air test.....all I have found was bringing it to 120 PSI for a short period of time then dropping it to 80 PSI for a certain period of time. Is this the preconditioning you are referring to? If not could you please explain?
That's it. There is probably a different but similar plan, but that is the one I was thinking of.

You have a real leak. Put bubble fluid on your gauge and Schrader valve. In fact, you can put a car valve cap on your Schrader valve. Those have a seal.
 

SMC_55

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I have used bubble fluid (Oatey brand) on the gauge and Schrader valve. I have even put bubble fluid in the air injection port and get nothing there. No leaks detected at that point. I am now thinking I could hook up a garden hose to it and try looking for the leak (or "puddle" as one poster mentioned...lol) I'm afraid I might get multiple puddles but hopin not.

So frustrating that I CAN'T FIND THIS DAMN LEAK ANYWHERE!!
 
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