The case for plastic lined nipples vs Di-electric unions.

[Bmusgrove]

I just replaced a 21 year old Whirlpool electric heater. Prior to doing this, I researched whether to use a dielectric union (as recommended by the new heaters manufacturer AO Smith), brass, or keep the plastic lined heat trap nipples that comes with the new AO Smith water heater. Opinions on this forum were varied.

For anyone else researching this in the future, I have attached pictures of the plastic lined galvanized nipples on my Whirlpool heater. This unit was in operation for 20 years. The interior of the nipples was clean. The exterior was so corroded you could deform the nipples with small pliers.

I’ll stick with plastic lined.


Hopefully this helps you in your research

your research.

 

[GrumpyPlumber]

Thanks for the pics.
Very common mistake with those, DIY's solder the adapter onto the copper pipe after threading it onto the dielectric nipple, melts the plastic & drastically diminishes tank life.