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Bob F Bob F is offline
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Default Mixing metals in water pipes


"Jeff Wisnia" wrote in message
news:RfednS_Fr6B3u5jVnZ2dnUVZ_q-jnZ2d@choiceonecommunications...
Bob F wrote:
I've done a bit of research on the subject. They say don't connect copper to
galvanized. Some sites say to use a dielectric union between then. Some say
brass can be used instead. I've seen dielectric unions with a hard copper
wire connected to both pipes - seems like that would defeat the purpose of
the union, but does code require it?

I currently have galvanized pipes with galvanized pipe coming into the house,
and am planning to replace the inside pipes with copper. There is a brass
valve at the entry. Do I need a dielectric union connected to that valve? Or
can I just connect copper to it? Should I use dielectric unions at the water
heater?


Rheem says you don't have to. See Page 5, Item 3, end of the fourth paragraph
of this document:

http://waterheating.rheem.com/conten...lecEclipse.pdf

I can testify that using dielectric unions between copper piping and steel
nipples screwed into the inlet and outlet openings of an electric water heater
wasn't the right thing for me to do the last time I changed out the heater.

While there is no "direct contact" of the copper and steel parts, there IS an
hard electrical connection between the two metals through the code required
electrical ground wire connected to the tank and the similarly code required
grounding of the copper plumbing system.


I am surprised the anode in the tank did not protect the nipples.

Do you suppose the the anode was similarly degraded? Or was it already gone?