View Full Version : Dielectric union V. Dielectric nipple
imadad2
03-28-2005, 08:14 AM
I installed copper pipe to replace galvenized pipe that had breakdown and leaks. A hot water heater was intsalled without a dielectric union. I went to my local plumbing place and asked for dielectric unions for my pipe. I was given dielectric nipples instead. Are they the same? Or should I have installed the unions instead of nipples. The gentleman I spoke to stated that they are interchangeable and that the nipple is easier to install. I agree with the ease of installation, but wonder if I am still endangering my galvenized pipe by using nipples instead of unions. Any input would be appreciated.
TonyBagadonutz
03-28-2005, 09:09 AM
I'm not a plumber (actually I'm an electrician), but I can tell you this:
A union and a nipple are not the same (ok, that was easy).
In order to prevent the "galvonic reaction"(oxidation) between the dissimilar metals, you need either a di-electric break(plastic washer or some other non-conductive element) or a metal that does not contribute to the galvonic reaction, such as brass.
What is the nipple made of?
imadad2
03-28-2005, 09:16 AM
What is the nipple made of?
The nipple is made of galvenized pipe and has a rubber/plastic tubing in the center. I used teflon tape on the threads and inserted one end in a female galvenized connection and the other end in a female copper connection. The gentleman I spoke to stated that the water going through the nipple cannot carry a current because of the rubber/plastic insulation inside the nipple. I took him for his word and because the nipple is so much easier to install.
Since neither is particularly effective, due to the water carrying the current, it does not make a whole lot of difference.
TonyBagadonutz
03-28-2005, 05:07 PM
Since neither is particularly effective, due to the water carrying the current, it does not make a whole lot of difference.
...that would explain why the big orange box store was selling the di-electric unions for 0.03¢.
Mike Swearingen
03-28-2005, 06:20 PM
I don't know much, but I know if you install regular galvanized nipples in a water heater instead of those di-electric nipples between the tank and the copper lines, they will corrode MUCH faster.
Go with the di-electric nipples.
Mike