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sleddoc
pin hole leaks in copper pipe

Last week I had the second pinhole leak in a copper pipe in my 19 year old house. I have a city water supply ( Maple Grove, MN ) and both leaks were on the main line just above the meter and the two main shutoff valves. I have replaced about six feet of the main line 3/4 inch copper in the area the two leaks were in. I saved the old pipe. I have a water softner, these leaks are before the water goes through the water softer. Both leaks or pin holes were about an inch from a solder joint or elbow. Is this common ?? can I expect more leaks or was this defective pipe ??. I am the original owner of this house, I built it in 1989 and it has always had a city water supply.

bp21901
Re: pin hole leaks in copper pipe

I'm thinking it may be from the flux used when soldering the copper since it so close to the elbow & joint. What was the condition of the saved pipe otherwise?

JLMCDANIEL
Re: pin hole leaks in copper pipe

It's quite common especially if to much flux was used when soldering. When the joint is heated the flux boils and pops and troughs small bubbles of flux which settle on the inside surface of the pipe. The flux is acidic and eventually eats through the pipe.
Jack

sleddoc
Re: pin hole leaks in copper pipe
bp21901 wrote:

I'm thinking it may be from the flux used when soldering the copper since it so close to the elbow & joint. What was the condition of the saved pipe otherwise?

Thank you for your reply: It looked almost perfect, some very small pits on the inside but otherwise solid.

sleddoc
Re: pin hole leaks in copper pipe
JLMCDANIEL wrote:

It's quite common especially if to much flux was used when soldering. When the joint is heated the flux boils and pops and troughs small bubbles of flux which settle on the inside surface of the pipe. The flux is acidic and eventually eats through the pipe.
Jack

Thank you for your reply: Doesnt the flux get washed away when the water is turned back on or in this case turned on for the first time ??

JLMCDANIEL
Re: pin hole leaks in copper pipe

When the flux is hot it is liquid once it settles on the inside of the pipe and cools it becomes paste again a sticky paste.
Jack

Re: pin hole leaks in copper pipe

this is most likely due to not reaming the copper tube to its full bore. its called velocity erosion when copper tube is cut with a tubing cutter it leaves a rounded over edge to the tube most people will just insert into the pipe and not think anything of it ( and i have seen other plumbers do this SCARY STUFF) the pipe needs to be reamed to its full bore or over time velocity erosion can occur. Now what happends is water travels threw the pipe when it hits the un reamed section this slows down the water flow then more faster water travels behind it with creates most force on the tube wich then causes water velocity erosion that slowly eats at the inner wall of the tubing and creates pitting and small pinholes hope this helps
- sean the plumber

bsum1
Re: pin hole leaks in copper pipe

Doesn't a 90 degree elbow cause restriction more than the unreamed edge? And how come it doesn't corrode those?

Re: pin hole leaks in copper pipe

90 is full port doesn't have a beveled edge to cause velocity erosion ( read my post more clearly)

bsum1
Re: pin hole leaks in copper pipe

I have read your post clearly.

Quote:

Now what happends is water travels threw the pipe when it hits the un reamed section this slows down the water flow then more faster water travels behind it with creates most force on the tube wich then causes water velocity erosion that slowly eats at the inner wall of the tubing and creates pitting and small pinholes

I was asking since 90's cause restrictions, which slows the water, how come the same thing doesn't happen?

Re: pin hole leaks in copper pipe

a 90 is full port meaning it does not taper down to a smaller diameter threw its bend and has the same id as a fully reamed copper tube.. the flow restriction is very minimal and a system installed with fully reamed tubes does not have major flow fluctuating thus eliminating erosion but it could be many things like water from a well source with old or no ph neutralizers
-sean the plumber

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