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Old 04-04-2019, 09:38 PM   #1
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Default Expansion Tank Connections

We just failed an inspection from threading a 2.1 gallon expansion tank (304 SS nipple) into a copper female adapter. First time in 35 years. The inspector and says it needs dielectric protection or brass nipple/coupling. IPC says "Joints between stainless steel and different piping materials shall be made with a mechanical joint of the compression or mechanical sealing type or a dielectric fitting or a dielectric union conforming to ASSE 1079".

Here's my dilemma's.
1. Copper and Brass are both at -.04 on the galvanic chart, BUT brass nipples and fittings contain zinc which is much more corrosive and prone to fail. Similar to the brass failures that have occurred in PEX fittings. Copper on the other had doesn't contain zinc and seems like the more logical choice.
2. If I opt for the dielectric union, I'll be threading the S/S nipple into the galvanized side of the dielectric union which is a dissimilar metal. Galvanized is zinc covered carbon steel and therefore much weaker than the copper adapter again.
Doesn't it make sense that copper to S/S is the best connection? Would love to here from an expert on the subject.
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Old 04-04-2019, 10:17 PM   #2
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Quote:
Originally Posted by Raleigh Plumbin View Post
We just failed an inspection from threading a 2.1 gallon expansion tank (304 SS nipple) into a copper female adapter. First time in 35 years. The inspector and says it needs dielectric protection or brass nipple/coupling. IPC says "Joints between stainless steel and different piping materials shall be made with a mechanical joint of the compression or mechanical sealing type or a dielectric fitting or a dielectric union conforming to ASSE 1079".

Here's my dilemma's.
1. Copper and Brass are both at -.04 on the galvanic chart, BUT brass nipples and fittings contain zinc which is much more corrosive and prone to fail. Similar to the brass failures that have occurred in PEX fittings. Copper on the other had doesn't contain zinc and seems like the more logical choice.
2. If I opt for the dielectric union, I'll be threading the S/S nipple into the galvanized side of the dielectric union which is a dissimilar metal. Galvanized is zinc covered carbon steel and therefore much weaker than the copper adapter again.
Doesn't it make sense that copper to S/S is the best connection? Would love to here from an expert on the subject.



The rubber bladder will fail before anything rots if you use enough teflon tape regardless of your materials for pipe. Especially if you're hanging it upside down, it sounds like you are.



The nipple should be on the bottom so any air stays in and if the bladder gets a hole it won't all piss out. Also, if there is a hole in the bladder than the air side will see less liquid.


I would say expansion tank into die union so galv steel on painted/galv steel, then sweat on the other half to your copper pipe.




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Old 04-04-2019, 10:22 PM   #3
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Also insulate the tank so the water won't cool and drop air into the wet side of the tank which could airlock it.




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Old 04-04-2019, 10:47 PM   #4
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Pipe it how the inspector wants it. When he signs off and leaves, switch it back.
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Old 04-05-2019, 07:38 AM   #5
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The inspector dont know what he is talking about....
the dialectric union has a very good chance of leaking due to the stress
at that joint... support it well if you actually have to do this to please the prick

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Old 04-05-2019, 08:27 AM   #6
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Originally Posted by Raleigh Plumbin View Post
"Joints between stainless steel and different piping materials shall be made with a mechanical joint of the compression or mechanical sealing type or a dielectric fitting or a dielectric union conforming to ASSE 1079".
What does the ASSE 1079 say for it's definition?

As a contractor the plumbing code isn't enough as we are supposed to know other codes from who knows where if the plumbing code doesn't have what you are looking for.

I had that issue with hammer arestors and when I asked the pipes mechanics they sourced it from an american code trying to tell me to follow that. Great! It's almost as if they are making stuff up following another code from another country!
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Old 04-05-2019, 08:28 AM   #7
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I don't call this in my area and don't recall a State inspector calling it. If I had this brought up while I was still working, I would go with a brass female before I would ever consider a Di-electric union.

@Debo, your just mean. Let me know your area so I can warn your inspectors.....
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Old 04-05-2019, 02:14 PM   #8
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Pipe it how the inspector wants it. When he signs off and leaves, switch it back.

just give him a $20.00 for lunch and all is good....
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Old 04-05-2019, 06:52 PM   #9
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I don't call this in my area and don't recall a State inspector calling it. If I had this brought up while I was still working, I would go with a brass female before I would ever consider a Di-electric union.

@Debo, your just mean. Let me know your area so I can warn your inspectors.....



Mean or not this happens ALL THE TIME, and with things more "important" than an expansion tank.



What bothers me about this is that the expansion tank will be a part of what he will be responsible for servicing under warranty so it would be in his best interest to do what he genuinely thinks will last longer. It's not like he is trying to cheap out using a stainless nipple instead of a dielectric, what's he saving? A dollar or two? I think the inspector should let RP do what he wants here.






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Old 04-05-2019, 07:52 PM   #10
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Quote:
Originally Posted by Raleigh Plumbin View Post
We just failed an inspection from threading a 2.1 gallon expansion tank (304 SS nipple) into a copper female adapter. First time in 35 years. The inspector and says it needs dielectric protection or brass nipple/coupling. IPC says "Joints between stainless steel and different piping materials shall be made with a mechanical joint of the compression or mechanical sealing type or a dielectric fitting or a dielectric union conforming to ASSE 1079".

Here's my dilemma's.
1. Copper and Brass are both at -.04 on the galvanic chart, BUT brass nipples and fittings contain zinc which is much more corrosive and prone to fail. Similar to the brass failures that have occurred in PEX fittings. Copper on the other had doesn't contain zinc and seems like the more logical choice.
2. If I opt for the dielectric union, I'll be threading the S/S nipple into the galvanized side of the dielectric union which is a dissimilar metal. Galvanized is zinc covered carbon steel and therefore much weaker than the copper adapter again.
Doesn't it make sense that copper to S/S is the best connection? Would love to here from an expert on the subject.
We service Durham, Raleigh, Chapel Hill area and all of our expansion tanks are hung on brass drop ear 90s, or copper females/brass couplings, or sideways with band iron to a wall (when using pex) I don't love the band iron method cause I think it looks sloppy, but that's just me......

This inspection correction is not one I have ever heard of, the most we ever hear of is not supporting it correctly. The "spirit" of the code (as we understand it) is to keep the stress of the weight of the tank off the fittings and pipe.

I have passed many inspections with the tank mounted vertically, nipple pointed straight down, straight shot to the heater nipple, this minimizes any stress on fittings and pipe, and looks nice in my opinion. And several passes using a drop ear to splice into the cold line in the crawl space if the heater location is too cramped, I don't love this one either, because then the tank is nipple up, and the weight of the water is contributing to bladder failure, but technically, it is not a reason for inspection failure. I also will sometimes build a shelf out of 2 x 4s, so I can use a drop ear, but with tank nipple down, if there is room near the heater location.

Never once had a problem with metals. In this area, those dielectric unions get plugged up quick, I hate them.

I would call the inspector and "fight" that one, respectfully of course.

Last month I had an inspector try to make me put a pan under a tankless in a sealed crawl space. I called bull, code states that is for tank style heaters, and besides that, replacement installs do not require drain piping from the pan to outside anyway.

So I asked the guy why would he subject the customer to more visits and me to more cost, if any leakage is just going to dump on the crawl floor anyway?

He agreed, and passed it.
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