Should I Be Concerned ??

[billt]

Yesterday morning as my wife was bringing in the groceries, she said she felt something wet hitting her. I went outside and I could see a small stream of water spraying straight up from my 1/4" copper supply line to both my evaporator coolers on the roof. I got a ladder and went up to take a look.

There was a pinhole in the 1/4" copper tubing about a 1/4" up from the nut on the valve, where it comes up through the roof. (Lower part of the picture). I had never seen a pinhole leak like that. There was nothing visible from where something could have struck it. It just sort of appeared on it's own. It was no big deal to fix. I simply replaced that 6" section of copper tubing with a new one, along with a couple of new compression rings. While I was up there, I also added another valve on the left side of the tee fitting, so I can shut off the supply to the cooler on the house, while keeping the supply to the garage cooler open. (We only use A/C to cool the house).

But the leak worries me. I read that pinhole leaks in copper pipe and tubing are not that uncommon. I have had copper plumbing on most every house I've ever owned, and never had an issue or a leak that developed on it's own. Have any of you guys? I have soft water, which I'm told really helps. I read if certain iron particles get stuck on the internal surfaces of copper pipe, they can cause a galvanic type of decay of the copper. And over time can cause a pinhole type of leak like I had.

The water supply that feeds evaporator coolers out here, are not plumbed through the softener. But rather bypass it. What say you guys? This was the setup that leaked. The pinhole was like I said. About a 1/4" up from the lower compression nut. It's all been replaced. I just hope it's not a warning of things to come.

[Solus]

Would PVC  or other less corrosive prone plumbing be worth considering?

And if I understand your setup, why not put in a valve on the garage run so that the house supply   for A/C can continue if problems develop on the garage side?
 

[billt]

I should add that when I cut into the existing copper line with my tubing cutter, to install the additional valve, I found nothing out of the ordinary when cutting through the old tubing. It was not brittle, nor did it feel thin. It took as much spinning and tightening of the tubing cutter, as it did to cut the brand new copper tubing for the piece I replaced.

[billt]

Would PVC  or other less corrosive prone plumbing be worth considering?

The biggest problem with PVC supply outside, (especially on the roof), is UV deterioration of the plastic itself from Sunlight. You can paint it, but even that cracks, and allows for UV deterioration after just a short time. I've heard PEX has issues with rodents chewing on it. Especially in attics. (It gives off a type of odor they like). And here in Lake Havasu the only PVC they allow under pressure, is for outside irrigation supply. And even that has to be copper where it exits the house.

Out here if you leave a piece of PVC pipe unprotected in the Sun for a year, it turns a deep purple color, and it will shatter like glass if you strike it on a hard surface.

[Rastus]

Galvanic corrosion can make a leak like that.  Because it is copper I don't think it could be a bacteria colony but could it be from a lightning strike?  Does your evaporative cooler have a slight short in it which is causing a voltage potential to ground..it doesn't take much over time?  And it may just be a bad piece of copper...if this is an existing home using chicom parts that may well be your problem.  I'd split that copper back at the failure point...I'm assuming it's seamless but maybe not. 

You could install your own "insulator kit".  You need to keep that copper from having any kind of a ground to avoid the galvanic corrosion.  I always install insulator kits on my well flowlines and sometimes zinc sacrificial anodes to avoid galvanic corrosion.  Since you are in the air with it...no need for the anodes...but maybe some zinc anode (like for an outboard) installed on the copper at the foundation.  I'd install a piece of PVC at the beginning and at the end to limit where you can have a problem with galvanic corrosion.  You'll have to slip some insulating materials in where the copper touches anything that will take it to ground....black electrician tape or a plastic/rubber sleeve or insulating material should do it.  Paint the PVC and cover it with insulating material or black electrician tape to keep the sun off for years.

[Sponsor]

[billt]

Thanks Rastus. I also read that vacation homes that sit several months out of the year unoccupied, can be more prone to this type of thing, than houses that are lived in year round. Water moving through the pipes on somewhat of a regular basis lessens the condition for this to develop. That makes some sense because my evaporator coolers are only used from around the end of April, until late October. They sit all Winter.

Maybe I should get in the habit of running them a few minutes every couple of weeks, just to get some water moving through them. It can't hurt.

[alfsauve]

I've had a leak where they bent a copper pipe to get it through a hole in a floor joust.  It was tight up against the joist and bent at that point.  After 40years between minute rubbing and chemical buildup at that point finally got a pinhole.

I think touching dissimilar metals and salts are the biggest problem with copper pipes.   

[Timothy]

This issue is common in homes with water heaters.  As they degrade because folks don’t change the anode often enough, metal particles travel thru the system and cause the copper to corrode and leak.

I assume your coolers are not connected to that system so there may be other issues with your a/c systems.

[PegLeg45]

Based from experience in industrial use of copper tubing (well, almost any type tubing made), sometimes it's just a defect in the material that's always been there but took years to show up. In a set-up like yours on a roof with no interference like rubbing against something via vibration then I'd say defect, unless like was mentioned above lightning got it.

On a roof, definitely stay away from PVC. Even painted and covered it'll go when you least expect it. My dad installed PVC irrigation stubs on our pecan trees years ago and even though they are in the shade 2/3 of the year we are constantly replacing parts due to exposure.
PEX is also susceptible to becoming brittle in the sun. Our camper water lines are run in PEX and the two system drain lines exit under the rear corner. About six inches of the lines used to hang down just far enough for partial sun exposure and I guess that was enough to make them brittle. We were camping a few years ago at Amelia Island and came back to the camper from lunch and the neighbor came over and said he's turned off the water supply because one of the lines at the back of the camper was spraying. It had a pinhole leak in the PEX just above the drain fitting. I went to Lowe's and got a Sharkbite valve and installed it and had to trim about four inches of PEX off the end to get rid of the brittle part.

If it were my set-up on the roof, I'd stick with copper or switch to stainless tubing. You could also go with aluminum tubing as well and be safer than PVC or PEX.

My two pennies worth.

[TAB]

Copper is fine.  Its speced for 40 year life span.  When it goes bad again you wont care.   If there  is no kink or damage to the line. A defect is the moat likely problem.  Remember this stuff is extruded by the mile and sold cheap.