Dielectric Union?

Thoughts on this please. I’m no plumber, but this looks like copper and galvanized to me. It’s a water heater connection. New home. The builder says it fine because the county code enforcement folks approved it.

My understanding is that a dielectric union is brass, and I must admit I sometimes have difficulty telling the difference between brass and copper. But the fitting is certainly the same color as the copper pipe, which you can see a little bit of at the top of the photo. Was I right to write it up?

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Looks like a heat trap fitting.



The heat traps are lined with plastic so the water never touches the steel nipple.

definately copper fitting

I have done alot of plumbing in the past but never heard of this heat trap thingy.
Is it some kind of fad or what is the story on these things.
Guess it would rule out use of a recirculating system.

Follow the links in my earlier post Bob.

Recirc lines still work fine BTW.:slight_smile:

Just got off the phone with the guy who put this in. He wanted to know what gave me the right to go behind a state inspector and claim something wasn’t right :shock:. I replied, “my state license”.

I sensed he didn’t understand the concept of corrosion that can occur between dissimilar metals. I said, “I’m not a plumber and don’t claim to be. If you can find a licensed plumber that will say this is OK, then he should clarify to me why it is. Are you a licensed plumber?”

“Uh, no”, he replied.

“I’ll email you the code and you can look it over. Have a nice day”, I said.

Good going.
It is always good to be confident

  1. There is no dielectric union in the photo.

  2. There is a copper fittng fitting 3/4" female pipe to 1/2’" sweat adapter(small for the outlet of a water heater)

3.The galvanized “nipple” is a heat trap fitting with a check ball built into it and is plastic lined(you can tell by the machined line in it and there is should also be a direction arrow on it)

  1. If the local AHJ approved it (which actually is not known for sure) Why fight. I don’t spend my time bucking AHJ’s. That doesn’t mean I don’t talk to them for their take on things.
    I would report what I find and the possible effects and move on.

Does anyone else see this differently? Just curious. :slight_smile:

Heat trap fittlings have nothing to do with galvanic corrosion.

When galvanized touches copper, you have galvanic corrosion, and a bad, prone to failure, connection.

I have had similar calls, from “electicians” (which are not state licensed, in Illinois), ‘plumbers’ and ‘roofer’ (which ARE state licensed, here, but these guys weren’t. They had the chutzpah (a jewish term for ‘affrontary’) to claim that because they had a local business license, that they were ‘licensed’.) and ‘licensed’ General contractors (which does not require a state license, in Illinois. Just get a 1 Mil G/L insurance policy and pay $35.00.) all asking what my problem was.

I merely ask, “Are you state licensed?”. After about 1/2 hour where they explain to me how they have been in business for 20 or 30 years, they finally say, “No.”.

I then, simply, explain to them that I have a State License and must, under law, do my job according to that law.

They are still pssd off, but at least they shut up.

Keep on doing what you are doing.

Educate the public, but also educate the tradesmen. They are, mostly, simple folk who don;t really know what they are doing, of the law behind it.

Hope this helps;

Read the second paragraph of the first link.


Galvanic action can be a bit confusing to understand so the following from the copper.org site may help clear it up.:slight_smile:
When dissimilar metals are in contact with one another in the presence of an electrolyte, galvanic action occurs, resulting in the deterioration of the metal with the lower galvanic number. The electrolyte may be rain water running from one surface to another, or moisture from the air containing enough acid to cause it to act as an electrolyte. LINK

*The plastic sleeve in the heat trap fitting does not allow the water(a weak electrolyte) to come in contact with the galvanized steel fitting. This will significantly reduce any flow of galvanic current. Hope this helps.:wink:

Makes sense to me.How often do you guys notice these heat traps?
Also how much energy do they actualy save.?

Exactly, and this is why a Dielectric Union is required in this situation.

Please explain as I used to believe that myself.

Beat the dead horse time. :wink:

See the top fitting from this LINK

They are ALL dielectric fittings.

For those who have not seen the effects of galvanic action on plumbing SEE THIS

The problem I see with the nipple style dielectric fitting is…

Once the nipple is installed we have No Visible way of knowing that the plastic (or whatever you want to call it) material has not been damaged, removed or tampered with in any way. With a traditional style dielectric union we are able to visually see the plastic protective barrier between the two dissimilar metals.

If I Can Not See Something, I Can Not Say That It Is There.

I have seen people using pliers trying to remove the plastic piece because they thought it was a cap used to provent something from falling in to the tank during shipping.

No disagreement with what you said.
You can’t tell on the ones without a label or without the groove that the heat trap ones have.

Wow… I guess nobody knows or I am chopped liver.

Having a plastic line does not always mean having a plastic seperation on the nipple. I see teflon, but know proof there is a plastic divider between the copper and galvanized.