Unions, Damn Unions!

[jmiller_2308]

No, not the organizations, those dang things that current MN plumbing code now requires on EVERYTHING!!!

Installing my new indirect water heater and as I go to rough in I do one last check of current codes. It has been awhile but things changed here in 2015/2016.

Now all connections to the water heater must include a union, and not only a union, but a dielectric union. Additionally, the circulator pump will also need to have unions.

If they don't leak it will be better but I'm bummed that I didn't verify code when ordering parts. This weekend project is now on hold until the next order of unions arrive. Sigh.... kind of like going to the hardware store multiple times for any other project.

 

[PCustoms]

Sometimes ignorance is bliss.

Is a union going to make the install safer in some way?

 

[Jim greengo]

Those dielectric unions leak like a sieve over time and rot away.
20 yrs from now when you need to replace the water heater again the size of the tank will be differant and you'll have to cut and replace everything any way.
Just somebody on a plumbing board/committee trying to look like their job is relevant by adding rules is all.

 

[BD1]

For best results just snug them and turn water on. If it leaks tighten slowly until it stops.
Most inexperienced tighten and compress rubber gasket too much. Over tightening will cause leak eventually.


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[txvwnut]

If you didn’t pull a permit for this I’d just install without the unions.

 

[yeldogt]

I hate those things .... they are always a pain. I never use them and I don't see any issues ..ever. Maybe in acid water

 

[jmiller_2308]

I generally get unions to work for me but they are an added expense, hassle, and since local stores don't carry 1" it is also an added delay while I order them.

I did pull a permit and because in MN it is now code to use unions for all wh connections as well as to use dielectric for all threaded connections of different materials that is what I'll do

Really had hoped to get the wh running this weekend but now it will be another week before I do.

 

[mcspeed]

Why pull a permit? The govt needs to take a step or three back.


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[acmikee]

the purpose of pulling a permit is to cover your *** if is causes a fire or something. the insurance company will use it as a means to not cover any damage

 

[rlitman]

...Additionally, the circulator pump will also need to have unions...

WTF?!? A circulator pump goes on bolted flanges. What's the point of a union there?

As for a dielectric union on your water heater, make sure that you've got a grounding bond across the pipes on the house side of the unions.

 

[LS6 Tommy]

Those dielectric unions leak like a sieve over time and rot away.
20 yrs from now when you need to replace the water heater again the size of the tank will be differant and you'll have to cut and replace everything any way.
Just somebody on a plumbing board/committee trying to look like their job is relevant by adding rules is all.

Not having a dielectric union will cause leaks a LOT sooner. Not all newer codes are dumb.

BTW, if the water heater has dielectric *******, most codes don't require dielectric unions.

Tommy

 

[jmiller_2308]

Why pull a permit? The govt needs to take a step or three back.

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Because of what acmikee says.

the purpose of pulling a permit is to cover your *** if is causes a fire or something. the insurance company will use it as a means to not cover any damage

I also tend to be a rule follower boy scout so whether I like it or not, I try to abide by the rules.

WTF?!? A circulator pump goes on bolted flanges. What's the point of a union there?

As for a dielectric union on your water heater, make sure that you've got a grounding bond across the pipes on the house side of the unions.

I had planned to just bolt the flanges to a male thread copper adapter as per the other circulator pump in my system until I got into the updated code. Last pump was installed 24 years ago and apparently things have changed.

I must admit that the old pump does have a bit of corrosion around the copper/iron flange joint but it is still solid as a rock and I'm not messing with it. Unfortunately, because of code, and being a boy scout, I'll be using dialectric unions on the new circulator pump. Luckily, I see that both Taco and Groundfos have flanges with sweat/thread that are already dialectric so I'll return my iron flanges and just use those.

Not having a dielectric union will cause leaks a LOT sooner. Not all newer codes are dumb.

BTW, if the water heater has dielectric *******, most codes don't require dielectric unions.

Tommy

No ******* from the manufacturer. Just threaded inserts into the stainless steel heat exchanger and water tanks. I'll be using stainless steel ******* connected to dialectric unions to connect to the copper piping.

 

[Jim greengo]

Not having a dielectric union will cause leaks a LOT sooner. Not all newer codes are dumb.

BTW, if the water heater has dielectric *******, most codes don't require dielectric unions.

Tommy

Newer code? Weve had those worthless things around here over 30 years.
I've seen plenty of old water heaters without them that have never had corrosion issues,lots of them were installed by me.

 

[LS6 Tommy]

Newer code? Weve had those worthless things around here over 30 years.
I've seen plenty of old water heaters without them that have never had corrosion issues,lots of them were installed by me.

Sorry, Jim. Bad phrasing on my part. I didn't mean to make it sound like I meant the dielectric union code was a "newer" code.

Tommy

 

[nadogail]

I am using SharkBite flexible lines on all my water heater installations. They work fine and they are easy. No failures in 19 years.

 

[rlitman]

...
No ******* from the manufacturer. Just threaded inserts into the stainless steel heat exchanger and water tanks. I'll be using stainless steel ******* connected to dialectric unions to connect to the copper piping.

Nooooooooo! Do not EVER use dielectric unions with stainless! Ever! That WILL cause corrosion that would not have otherwise happened.

Dielectric unions are plated steel on one side, and that will corrode on the steel side when connected to stainless. Stainless should be directly connected to brass or copper (and NOT galvanized or plated steel). Look at a galvanic chart.

As for the pump, is this a DHW circulator, or boiler loop circulator? On the boiler loop, copper can connect directly to iron, because the closed loop water is free of oxygen. On DHW, you want a bronze pump with bronze flanges. No iron touches DHW, and still no dielectric unions on pumps.

 

[LS6 Tommy]

Nooooooooo! Do not EVER use dielectric unions with stainless! Ever! That WILL cause corrosion that would not have otherwise happened.

Dielectric unions are plated steel on one side, and that will corrode on the steel side when connected to stainless. Stainless should be directly connected to brass or copper (and NOT galvanized or plated steel). Look at a galvanic chart.

As for the pump, is this a DHW circulator, or boiler loop circulator? On the boiler loop, copper can connect directly to iron, because the closed loop water is free of oxygen. On DHW, you want a bronze pump with bronze flanges. No iron touches DHW, and still no dielectric unions on pumps.

SS and zinc coatings are fine together, as long as there is a high level of zinc. The zinc is the sacrificial metal and it protects the base steel. Lower levels of zinc on a dielectric fitting actually corrode the base steel more. Dissolved O2 increases corrosion, but you still need a dielectric fitting.

Domestic pumps can be SS, too.


Tommy

 

[jmiller_2308]

Nooooooooo! Do not EVER use dielectric unions with stainless! Ever! That WILL cause corrosion that would not have otherwise happened.

Dielectric unions are plated steel on one side, and that will corrode on the steel side when connected to stainless. Stainless should be directly connected to brass or copper (and NOT galvanized or plated steel). Look at a galvanic chart.

As for the pump, is this a DHW circulator, or boiler loop circulator? On the boiler loop, copper can connect directly to iron, because the closed loop water is free of oxygen. On DHW, you want a bronze pump with bronze flanges. No iron touches DHW, and still no dielectric unions on pumps.

ARGH!!!! I have read arguments both ways as to whether stainless direct to copper will or won't work.

Most argue for stainless to copper or at the very least stainless to brass. Arguments against say stainless will rob from the copper and cause the copper to corrode and this seems to be supported by the galvanic chart.

However, your point about the dielectric union being "plated steel" was a good slap in the face. Assuming the plating is zinc the chart shows zinc is a LOT worse to connect to stainless than copper is.

So since the WH has female threaded stainless I still want to use stainless ******* to connect to it. By code I still need to have a union at the WH. Should I use a female copper adapter to connect the stainless ****** to an all copper union? Or maybe a threaded brass union?