Mystery Line Bulge

[jaysongoff]

I was on a call last year where I had a leak over a walk-in freezer. I couldn't help but notice the huge oil slick on top of the riser. When I looked at the installation, I figured it was a rookie welding up there and decided to cut out the section and re-pipe. I looked down inside of the pipe and got a big surprise. Check out these pics.
Jayson

[referrob]

was working on supermarket systen and had a leak that was hard to find because it was detectable throught the whole store. finally found it in a corner between the dairy multi deck and milk wialk in cooler. long story, short it had that same strange defect. took it to my instructors from my school daze and they couldnt explain it nor could anybody else. never seen that before was the only answer i could get. my theory is that grit from sanding got in the joint and during heating gassed off creating the bubble. i used a band saw and cut the pipe to pieces to further investigate but found nothing out of the ordinary. kind of cool to see another one.

[len]

that there,looks like a john wayne belt buckle.:D

[stevenj]

moisture working into the joint,joint not fully capped ,or pin hole in capping, which allows moisture to work it's way in freezing then
causing expansion between the surfaces of the fitting and the pipe. pressure created by ice as it is formed and expanding is very
high.

[icemeister]

moisture working into the joint,joint not capped with braze material.

I agree. The freeze/thaw of the trapped moisture over time will cause this type of bulge. The same thing can happen with flare connections like at the TEV outlet.

[stevenj]

have found frozen food cases with plugged drains,that the bottom tubes of
the evaperators had been crushed due to ice..

also took over a store last week that is in the snow belt area of north east
ohio, that snow had been drifting up against a vertical condenser, well
the freeze thaw crushed the bottom rows of the coil.

[jaysongoff]

Thanks youall.
I felt it might be ice damage but wasn't sure. The install of the insualtion was improper allowing for excessive frost to build near this section of piping.
http://www.hvac-talk.com/vbb/images/smilies/biggrin.gif
:D

[push 2 reset]

that appears to be whats called a frost pinch,the copper is weakened oviously due to brazing moisture gets trapped. this happens to flare nuts , in this case use frost proof flare nuts hope this clarifies