Tested a new main shutoff valve with air, worried about underground leak

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yannick

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I've been replacing the plumbing since awhile in my house. Water was shut at the city valve service box on my front lawn in September (I don't live there yet).
I got delayed because of stuff outside the plumbing, in my general life.

Mind, this is in Canada, cold winters, so underground lines are 6ft deep and below the basement floor, and it pops out of the basement floor. I cut in january that section, and proceeded to learn how to solder ball valves, so I had a few tries on the line.

Recently I soldered what would be the final try for my main shutoff ball valve (the first "line of defense" in the basement basically, after that it would be the underground service box valve that connects to the city). And then I soldered to it a fitting to connect a compressor hose. I wanted to test it for air leaks.

In january, when I cut the previously existing old gate valve, there was no water in the vertical section going from the basement floor to the ceiling of the basement (I never had touched it before).
At the time I was already surprised and suspected a leak could be the cause. I had left a few sinks open since September, I thought maybe there had been evaporation, so I didn't mind about it.

Today I proceeded to do turn on the compressor at the new main valve I soldered, but to my surprise, it seems the pressure gauge needle doesn't go past 22psi. As if there was a leak in my underground line. I'm starting to panic.. Obviously, it would cost a lot to replace that line.
On the polybutylene pipes I removed, I see a brown film inside the pipes as well, could that be soil in the line?
I wonder what should I do next... I never put too much flux when soldering, I highly doubt I damaged the pipe myself. I don't feel air between the floor and the main shutoff ball valve I soldered, so the section of the pipe above my basement floor doesn't leak.

Could it be that the service box valve has a system that releases the pressure when that valve is closed? In other words, I wonder if it could be something else than an underground pipe leak, something else than the worse that could possibly happen.

P.S. My underground line is type K copper btw. We don't pay for water, so I don't have a water meter to my knowledge.
 
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Jeff H Young

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does the pressure drop or hold at 22 compressor shot? I cant tell you if you have a leak you have to determine like a ball or bike tire you cant tell I cant. could be faulty equiptment but it shouldnt be a mystery toilet fill valve might be letting air past is a possibility?
 

Reach4

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It probably goes without saying that you have tested that your compressor can still put out more than 22 psi.
 

WorthFlorida

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Is the pressure test at the main valve to the meter only?
Is the valve turned off so the rest of the home is closed off?
Where is the pressure gauge in this setup?
Where and how are you connecting the air compressor hose?
Any pictures you can post?
 

Jeff H Young

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It seems to me Yannick is testing the entire house to the main with air. and presumeably the other side of valve going out to the street not under test .
 

wwhitney

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It seems to me Yannick is testing the entire house to the main with air. and presumeably the other side of valve going out to the street not under test .
I believe it's the opposite. The house plumbing has been disconnected from the main, the water valve at the curb is off, and a new main shutoff has been installed just inside the building. The pressure test is of the underground lateral between the curb shutoff and the new house shutoff.

Cheers, Wayne
 

Jeff H Young

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I believe it's the opposite. The house plumbing has been disconnected from the main, the water valve at the curb is off, and a new main shutoff has been installed just inside the building. The pressure test is of the underground lateral between the curb shutoff and the new house shutoff.

Cheers, Wayne
Yep you I think are correct so back to basics if he cant get over 22psi air in it Im going out on a limb and say faulty test /equiptment or he has a leak
 

WorthFlorida

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Yep you I think are correct so back to basics if he cant get over 22psi air in it Im going out on a limb and say faulty test /equipment or he has a leak
It what it sounds to me but you may never know when someone writes his situation down. Is the pressure test with the new valve open and the pressure hose is connected to the end or is it tee'd off before the valve? If I understand correctly the old feeder line is what is being used and only replaced the shut off at the house, therefore, the old line could always have been leaking since there is no meter.
 

yannick

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Sorry for the confusion my post in convoluted.

I'm testing like this :
Compressor+gauge ---> Ball valve I soldered near basement floor ---> Type K copper line that goes underground ---> Service box valve (closed by the city)

Any plumbing above is not connected (toilets, sinks, etc.)

Image :
20230408_214102__.jpg


We are at basement level here. My compressor is a 6 gallon 150psi (Porter Cable pancake). When I close my ball valve (the one with a white handle), the pressure takes off to about 130psi and stays constant overall. When I open the ball valve, I get maxed at 22psi and hear a copper hissing as well.
As the air flow would be quite easy to feel, I put my hand around the pipe near ground level, and can't feel any air gushing out.

What would be my next course of action knowing these facts?
 
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Jeff H Young

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Ok so if you leave the valve open after 10 minutes it still isnt rising , Ive got an Idea with compressor on and steady pressure Walk out to the box lift lid listen then follow where you hope pipe is in a straight line lintening as good as you can and over to the basement wall where you know it passes Im talking about 5 minutes time or what ever maybe walking with a pipe to your ear . then if you dont hear anything you have 2 choices excavate and dig new , or hire leak detector (I never did this on 6 ft deep lines)
 

John Gayewski

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22 psi seems low but if you test a pipe with air and it has water in it, you will loose most or all of your pressure for a very long time. Eventually it will balance out when the water can no longer absorb air at that the test pressure.

But like I said it should build above 22 psi, or at least one would think it should.
 

yannick

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Yes I drove a camera into it and about 2-3 ft deep from the valve point (in the picture), there's water which makes it impossible to see further.
I maybe have assumed too fast the pipe was bad and did turn off the compressor pretty quickly thinking about it now.
It ran nowehere near 10 minutes. Not even 5. Probably 1-2 minutes.
I'll try longer next time I go.
 

John Gayewski

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If I were you I'd just have them turn it on. If there is in fact a leak that you can't see, you'll never find it with the water off anyway. As long as your not getting any air from the sweat joint before the valve which you should be able to see with dish soap and water mixture.
 

Jeff H Young

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I think op says his pipe will not pump up above 22 psi with a compressor thats not water absorbing air.

Yea turn water on I guess you guys have to call and ask ours is shallow we all have a key
 

John Gayewski

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I think op says his pipe will not pump up above 22 psi with a compressor thats not water absorbing air.

Yea turn water on I guess you guys have to call and ask ours is shallow we all have a key
We have keys you can get a pretty good reaming for using them. The city owns the valves and people ruin them.
 

Jeff H Young

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we use them very often but they are only like 10 inches deep and good ones turn easy. I go to a house with a shitty gate valve I go straight to the curb stop even with water company there. but If I was in some unfailiar territory Id Tread lightly!
 

yannick

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Sadly, after running 20 minutes the compressor, pressure did not build up past 20 psi.
The underground pipe is most probably leaking... and beside, I learned today underground pipe repairs are not legal here. Gotta change the whole thing anyway...
 

Jeff H Young

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Did you listen for air at the box? 6 foot deep thats crazy! we bury at 18 inches , dug them solo by hand I know why I just mean the differance.
 
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