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srobb
Corrosion around hot water heater connection?
srobb

I installed an electric hot water heater about 3-4 weeks ago. Everything has been operating without problem and there have been no detectable leaks around the water connections into and out of the water heater. However, I discovered what could be some corrosion starting on the hot water side. The connection is a stainless steel flex pipe without tape or compound (the pipe's tag said not to use any). I believe the hot water side connections are galvanized steel.

Is it possible for corrosion to form so quickly and if so what should I do about it? My first thought was to disconnect, cleanup, and try again with a new line. How quickly should I act?

bill
Re: Corrosion around hot water heater connection?
bill

First off when you connect dissimilar metals this creates a galvanic reaction between. stainless to galvanized nipple of the hot water tank. In this case the nipple will rust out very quickly. What a real plumber will use is a di-electic fitting to separate dissimilar metals. This why you should hire a real plumber, he knows stuff that only a very few know,

Bill

johnjh2o
Re: Corrosion around hot water heater connection?
johnjh2o

Sounds like a small leak to me. What Bill said is very true but it would take longer then three weeks to show up.

dj1
Re: Corrosion around hot water heater connection?
dj1

Almost all new water heaters come with factory installed dielectic nipples for hot and cold. No new water heater comes with factory installed galvanized nipples.

You didn't mention whether the water heater that you installed 3 weeks ago was brand new out of the box.

For a quick solution, replace the nipples.

You also asked about using teflon tape or plumber's dope. If you use flex copper/stainless steel supply connectors, they come with rubber washers and require no tape/dope. Check your connectors to verify that they have washers inside.

It's a good practice to use new connectors when replacing the water heater.

Fencepost
Re: Corrosion around hot water heater connection?
Fencepost
bill shack wrote:

First off when you connect dissimilar metals this creates a galvanic reaction between. stainless to galvanized nipple of the hot water tank. In this case the nipple will rust out very quickly. What a real plumber will use is a di-electic fitting to separate dissimilar metals. This why you should hire a real plumber, he knows stuff that only a very few know,

Bill

The flex pipes (whether stainless or copper) generally have a plastic bushing between the flex and the nut, and a rubber or neoprene washer between the flex and the pipe being connected to. If those bushings and washers are in place, then it's a dielectric fitting.

If you can post a picture to a file sharing site and set it to be publicly viewable, post the link here (attachments don't work on this site). That will help us make a better judgment.

dj1
Re: Corrosion around hot water heater connection?
dj1

Right after I bought my first rental, straight out of college, I had a water leak. The plumber who came fixed it and said something like: "Thank goodness for galvanized". When I asked him what he meant, he grinned and said: "galvanized keeps me an other plumbers in business", collecting his money for the quick visit. "You see all these homes around here?" he continued, "they all have galvanized pipes and connectors - enough money for us for generations to come"

srobb
Re: Corrosion around hot water heater connection?
srobb

Link with picture of connection in question:

http://i.stack.imgur.com/RWbsF.jpg

dj1
Re: Corrosion around hot water heater connection?
dj1

OK, we have a picture.

It's hard to see exactly what kind of nipple you used, without disconnecting the flex connector. Some di-electic nipples may look like galvanized, but they have a plastic tube inside them. Also, what was the white stuff that you smeared on the nipple thread?

The discoloration may or may not be a sign of early rust, a fact that can be determined by examining the inside of the nut of the flex connector, once it's removed.

Mastercarpentry
Re: Corrosion around hot water heater connection?
Mastercarpentry

The flex tube seems to be the 'dielectric' type but it never hurts to use dielectric nipples anyway. All the new W/H's I've seen in the last few years come with those supplied or installed.

Phil

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