What causes this?

There is some corrosion or other buildup on this cold water valve. It is to a gas water heater in a closet. The valve body is brass and the lines are copper so it shouldn’t be galvanic corrosion. There is a ground wire from the electric panel attached near the wall. see picture

I was under the impression that brass & copper will result in galvanic action just on a smaller scale since they are close together on the galvanic table but corrosion will occur. I’d say it is galvanic corrosion.

May be so but this table says that the difference between copper and even high brasses and bronzes is only 0.10V and standard brass and bronz is only 0.05V Even for a harsh envrionment, 0.15V is listed as being acceptable. That’s why I thought it wasn’t galvanic.

:shock: Looks like it might be hard water residue… then again I could be blowing smoke:shock:

I call that a leak. Needs to be repaired by a plumber.

Not supposed to have hard/soft water residue on the outside of piping.:slight_smile:

A leak? A simple leak from plain old water? That’s too darn simple. Naaahhh, it’s just gotta be some complex chemical reaction caused by a confluence of substances that only get together under conditions induced by alien forces or something like that… A leak? Come’on… -X

Ron, when I am writing my reports I try not to get all CSI/Coloumbo as to the cause.
Could be faulty material, could be to much flux during soldering (my guess), could be cleanig supplies nearby.

I don’t care, it’s broke-fix it.:slight_smile: Next inspection please.:slight_smile:

Or you can go with the allien force confluence thing, my guess is it will be a niche market for your services.:wink:

i argued with a realtor (go figure) about a crack in a sink trap that was glued with “goop”, and i said that same phrase, word for word. and it was also the last word for that drain. the seller came in the door 2 minutes later with a bag of pvc parts and glue from the Depot. love it.

Small minds think alike Jay:) :slight_smile: :slight_smile: :slight_smile: :wink:

Galvanic action, no doubt about it. Put together the dissimilar metals and then add in the possability of the odd stray current that comes down the ground connection and you have a perfect environment for galvanic action. Add hard water into the mix and the problem gets worse. The green on the copper is a lazy plumber not wiping the joint to get the “flux outta here.”

The white product is the result of a small leak that has managed to seal itself up, if you scrape it off it will leak again. I see this all the time in boiler rooms that people frequent often.

Ditto…I wipe off the residue also, bingo…generally a very minor leak occurs if it has not sealed itself completely.

I never wipe of "crust " from a suspeced leak, what’s the point? Why make it active? As for galvanic action brass and copper are very close not much going on there.

That is why the crust is forming, it is drying as fast as it is leaking…I’m not causing an active leak…it is active…:smiley:

It drys especially fast in a location where its nice and warm…generally most places here…:shock:

Fine fine fine, why increase the activity???:smiley: :smiley: :smiley: Since we are in agreement the the activity is not good.:wink:

I also like when the realtor asks my “what code says that?” and i simply reply, “not sure of the actual code, or if one exists, but codes are writen for people to follow because some where someone found out the hard way that what was once done is now know to be unsafe, and for good reason.”. that usualy shuts them up…for a couple minutes anyway.

Galvanic corrosion combined with somewhat high mineral content in the water. If they fix it, it would be interesting to get a look at the inside.

At areas where there is galvanic activity, minerals in the water tend to cake on the interior of the pipe, especially at joints, where the end of the pipe is exposed. This buildup, over time, tends to change the ionic composition of the joint and leads to more buildup, then more galvanic activity.

So much for the physics lesson. I agree with, “It’s broke. Fix it. Move on.” No reason to write a paper, it’s bad. Let the plumber deal with the fix.

Of course you don’t wipe it off, if you did your in the wrong trade. Have them call a plumber, there is corrosion taking place on the unsoldered piece of pipe inside the joint and it will get worse.

One question, how old was the house? That small of a difference in the anodic index will take many, many, many years to develope. If it is a very old house I might believe the galvanic corosion, otherwise I tend to thinks it is a simple leak.

So, how do you report it? “Conecttion at valve shows evidence of leakage or excessive corrosion…”?

“Seems” ought be be able to identify it as one or the other…