Di electric union keeps corroding

[NavySuit]

I replaced my hot water heater 3 years ago. I remember having to replace one of the dielectric unions about a year after installation. I can't remember if it was the hot or cold side. Now, the hot side union is corroding. The cold side is fine. Why do you think this is happening? I added the unions to prevent the dissimilar metals from corroding.

 

[Terry]

Are you sure that's only three years old?
There may be moisture there causing some of that.
In Washington State; earthquake country, we use flex connectors . Those hold up much better than what you have.
I've installed one dilectric union in 40 years. The ones I pull out all look bad.

 

[Sponsor]

 

[Cacher_Chick]

I would cut that off and replace it with a 6" brass pipe nipple, which will accomplish the same thing.

 

[Master Plumber Mark]

you need to take those unions out and install a couple of brass nipples then 2
flex poly connectors like Terry has already stated... the flex connectors are like installing dialectric unions but they are 10 times better

 

[NavySuit]

I thought it was necessary due to the dissimilar metals. I guess the manufacturer puts the dielectric nipple in the tank anyways.

We don't have earthquakes down here in Florida. I see most hot water heaters connected with the copper flexible pipe. I tried to hard pipe it in for a cleaner look. I wanted to add a union.

What are my options? Will the 6" brass nipple cause corrosion issues at the tank connection?

 

[NavySuit]

you need to take those unions out and install a couple of brass nipples then 2
flex poly connectors like Terry has already stated... the flex connectors are like installing dialectric unions but they are 10 times better

\

Are you referring to a braided flex connector? Are they more reliable than copper flex connectors?

 

[Terry]

I use copper flex connectors. I've never used a braided connector for a water heater.

 

[Master Plumber Mark]

I use copper flex connectors. I've never used a braided connector for a water heater.

Terry,,, what are you paying for the flex copper connectors???

The copper flex connectors work fine and have been around forever..
. We do see them spring pinhole leaks after maybe 10+ years out so they are very reliable....
they just dont bend as well as I would like them to..

I like the Brass Craft poly black connectors because they are more flexable
they cost me about 10 bucks each and save tons of labor time and fittings too

 

[Terry]

$8.25 for the copper 24" flex
I think they bend real well.
Thread one side of the flex on loosely, and then holding the nut on the other end of the flex in your hand, guide it to the nipple on the water heater.
If you have snugged up the wall side nut, this doesn't work.

 

[Master Plumber Mark]

Where are you getting them for 8.25?? I can only find them on line for about 14 dollars??


We did used to use them a long time ago with female connections on both ends....
They do work well till the electrolysis eats pinholes into the bends...

I cant touch them for that price around here so we just do the black braided ones and have
had almost no complaints....

 

[hj]

Plumbers do NOT buy their materials 'on line'. That is a DIY thing. 99+% of the heaters here are connected with flexible copper connectors, and I cannot remember when the last time was when I found one with a hole in it.

 

[Terry]

I buy from several local plumbing supplies. I've known the guys on the counters for decades.

 

[FullySprinklered]

I would dearly love to use flex connections of any type on my water heater installations. Around here it adds quite a lot to the materials expense for replacing a water heater. We're talking 35-45 additional bucks on an already expensive service call. The customer is paying me 400 dollars labor, up to 600 dollars for a 12-year warranty water heater, plus fittings and materials, expansion tank, reworking non-code compliant pop-off line, etc. Where does it end?

 

[Master Plumber Mark]

Plumbers do NOT buy their materials 'on line '. That is a DIY thing. 99+% of the heaters here are connected with flexible copper connectors, and I cannot remember when the last time was when I found one with a hole in it.

HJ...If I could buy them for 8 bucks each on line, I probably would buy 50 of them tonight...PRICE is all that matters, and it dont mean you are a pussey or a DIYER if you find a great deal on some of them on line....

I think that they work great and are better than dialectic unions ...
PRICE is my only complaint

I got probably 6 of the copper ones in my trash bin,,,
I took 2 out on Saturday morning where
a pin hole on one of them had flooded the area .

You have to admit that the copper in these flex supplies is very thin and around these parts they seem to corrode in the bends, turn green , and finally leak....
but they still seem to last a long time on average

this was at least 12 years old or more...
no complaints but I am not paying 16 bucks each for them

Terry, so why dont you buy me 50 of them and ship them to me for X-mas....???

I can feel the love already

 

[Master Plumber Mark]

Terry, I am not feeling the love yet...
how about 25 of them??

 

[Terry]

I can get the corrugated stainless for even less.

 

[Master Plumber Mark]

I can get the corrugated stainless for even less.

Have you ever tried the SS ones??
Do you like them or do you prefer teh copper ones??

I can get the SS ones for about 7 bucks each...



no joking aside.... if you dont want to send me an x-mas present

so how much would you ship me a few dozen of the 24 inch copper ones for ??

 

[spete112]

I realize every part of the country does things a little different. However what is the need for any of these fancy fittings. All a person needs is a male/female adpt and a copper pipe, coupling. Then take it from there ball valve, pex adpt or what ever you need. What does a union do for a person? You are already doing some sweating and what are the chances of your next WH being the same size. Just interested in hearing peoples opinion.

 

[Master Plumber Mark]

I realize every part of the country does things a little different. However what is the need for any of these fancy fittings. All a person needs is a male/female adpt and a copper pipe, coupling. Then take it from there ball valve, pex adpt or what ever you need. What does a union do for a person? You are already doing some sweating and what are the chances of your next WH being the same size. Just interested in hearing peoples opinion.

it has got to do with a blind mind-numbing habit.... that is how they have done it for decades..
The diaelectric union is nothing but trouble mostof the time and they corrode shut..
personally just like Terry does,,, install a couple oc copper flex connectors directly to the
water heater and you are good to go......

 

[Jadnashua]

When you use dissimilar metals tightly connected to each other in the presence of an electrolyte, they create an electrical current. Water in most situations is not pure enough and therefore acts like an electrolyte. That current causes one metal to dissolve/corrode in the process. The flexible hoses use a gasket to make the seal, and thus, at least where water can get, the two different metals do not touch. The dielectric union has a plastic liner that tries to do the same thing, but that can be destroyed if you solder a pipe near it. The amount of current depends on several things, some of which is how different the metals are, the temperature, and how good of an electrolyte you have. Sounds like your water may have some salt or other minerals in it making it more reactive or someone is soldering too close to finish up the connections..