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  #1  
Old 11-09-2012, 05:31 PM
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More plumbing

Why plumbers should know something about galvanic action:

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  #2  
Old 11-09-2012, 10:09 PM
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I have copper male adaptors that thread directly into the older iron pipe. This allows the changeover to copper in the basement.

Always bothered me...............
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Old 11-09-2012, 10:52 PM
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Yep, bad idea. I always use dielectric unions when joining copper and iron. The galvanized away from the copper was still in pretty good shape, definitely useable for a few more decades.
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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
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1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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  #4  
Old 11-10-2012, 12:49 AM
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A length of brass pipe is supposedly sufficient to mitigaste the worst of it. Although I have a theory that it merely slows it. Some of the worst rust I find is at the junction of galvy to brass angle stops/shutoff valves. You open steel to steel downline, same circuit, and it's not as bad. The dialectric unions are cheaper than brass niples anyway.

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Old 11-10-2012, 07:05 AM
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Quote:
Originally Posted by cmac2012 View Post
A length of brass pipe is supposedly sufficient to mitigaste the worst of it. Although I have a theory that it merely slows it. Some of the worst rust I find is at the junction of galvy to brass angle stops/shutoff valves. You open steel to steel downline, same circuit, and it's not as bad. The dialectric unions are cheaper than brass niples anyway.

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Old 11-10-2012, 08:18 AM
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And don't forget. If your house electricity is grounded (common to most houses built pre 1980's) via the water line and you install a dielectric union you need to install an earth/grounding spike as a replacement ground. Don't do as a buddy of mine did. He simply added a "jumper" around the union. Kinda defeated the purpose.
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Old 11-10-2012, 12:42 PM
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I'm guessing the ground connection is closer to ground, that is back on the original iron piping. Good point though, that would be one reason to use a brass piece in between.
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Old 11-10-2012, 02:44 PM
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adding a good 10+ ft ground rod never hurts. i need to replace the one here at my house. im assuming they used steel originally and it has rusted away.
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Old 11-10-2012, 07:52 PM
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Impressive, Something simular happened with our train, they used galvanized pipe mixed with black pipe, the main steam valve had a galvanized nipple on it, it erroded through and we got a very bad steam leak, it diddnt blow but the pipe looked just like that one
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Old 11-10-2012, 08:30 PM
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Yes steam pipe would be worse. That picture I posted is of the hot water line. The cold water line wasn't as bad but it was still corroded. The heat accelerated the process.

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1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13
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