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I have always seen the argument back and forth between whether or not you should put a dielectric union on the nipples for a w/h even though the majority of w/hs have dielectric nipples already installed.

I've always seemed to have issues with dielectric unions clogging up with junk over time, but I'm indecisive on whether or not I should be using the unions at all, or just threading an FIP adaptor on and calling it a day
 

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Any master I’ve worked for uses them on heaters, so I do. I do see an advantage in some apartment complexes for a simple swap out. Do I believe they really make a difference? Nope. The inspectors like to see them. F’in overloads! I really think they only make a difference when connecting to old galvi.
 

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Any master I’ve worked for uses them on heaters, so I do. I do see an advantage in some apartment complexes for a simple swap out. Do I believe they really make a difference? Nope. The inspectors like to see them. F’in overloads! I really think they only make a difference when connecting to old galvi.
I make nothing easy for the next person..as that next person could be some hack that you made it easy for them to do plumbing work...
whatever the heater comes with is what they get, I never added dielectric unions to anything...
the gas meters that are supplied by the gas company have dielectric unions as an integral part of the meter bars they give out...
 

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Brass adapter here. Brass is a neutral metal so no corrosion. Never seen a dialectric union on a water heater in my life.
 

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My boss claims to have seen the copper female adapters corrode out and leak badly. For that reason he wanted us to switch to using dielectric unions (my bad for telling him about them when he complained about the copper females). Around here there are never dielectric unions on the old heaters but some times a regular union. That union is worthless anyway as all new heaters are taller than the old ones. I hate dielectric unions for the reason that they clog up. The few I have taken out always look like these pictures I took. I use a brass female adapter.


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Yep brass unions, wont' corrode up. Never copper on the galvanized threads on a heater galvanic reaction will take it's toll.
 
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If you install an HTP tank it says right on it " do not use dialetric unions it voids warrany".
Then i unthreaded them an went an bought 1-1/2 bar stock females lol

You're corrrect the HTP stainless steel tanks require you to install copper directly to the tank. Di-electric unions void the tank warranty.
 

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Discussion Starter #10
Brass adapter here. Brass is a neutral metal so no corrosion. Never seen a dialectric union on a water heater in my life.
You see I've heard people argue that, too.

I've heard most of my mentors say you need at minimum 6" of brass, but then people here say that a simple brass FIP will work, or a brass union.

Does the 6" rule really matter that much?
 

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I'm pretty sure my UPC code states that water heaters must be connected with eighter a dielectric union or 6" of brass. I hate dielectric unions so that's a no for me. Now with the water heaters all having dielectric nipples these days I am good with just the brass fip adapter.

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You see I've heard people argue that, too.

I've heard most of my mentors say you need at minimum 6" of brass, but then people here say that a simple brass FIP will work, or a brass union.

Does the 6" rule really matter that much?
Never heard of that 6" thing. 3/4" Female adapter and copper, That's all I've seen in 26 years.

Nowadays brass adapter and straight to pex.
 

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Never heard of that 6" thing. 3/4" Female adapter and copper, That's all I've seen in 26 years.



Nowadays brass adapter and straight to pex.
Straight to pex hmm. Here UPC and most manufactures require 18" of ridgid metal tubing before going to any plastic piping.

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why? once you go pex it is what it is who made that law?
I believe its something to do with in case the tank overheats then that first bit of metal piping can give off some of the heat in the first 18" so the heat from the tank rising up will cool down a little before hitting the plastic pipe. Honestly no one I know of has an answer but it is the code.

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Straight to pex hmm. Here UPC and most manufactures require 18" of ridgid metal tubing before going to any plastic piping.

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why? once you go pex it is what it is who made that law?
Direct pex or poly-B for the last 30 years, no issue that I've heard of and code for us.
 

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You see I've heard people argue that, too.

I've heard most of my mentors say you need at minimum 6" of brass, but then people here say that a simple brass FIP will work, or a brass union.

Does the 6" rule really matter that much?
The minimum 6” of brass is between galvanized pipe and copper to prevent electrolysis. They’re probably thinking it’s the same on water heater nipples.
 
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