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Tankless Tom · Nov 12, 2007, 04:48 PM

"Speedball Tom",

Let me first say that since this is my first post, I mistakenly submited it as an answer to one of "Speedball's" answers to someone else on the same subject. My apologies.

Greetings from "Tankless Tom". I started my search on Google with the term: "dielectric union" to try to answer a question I have about the effect their absence may or may not have on the rest of the plumbing in the house, specifically various valves and fixtures.

The house was owned and lived in by our family, but is now being rented out. It is about 40 yrs old. I installed a solar hot water system in about 1982 which is still working but about to spring leaks. We plan to take it all out and install a tankless water in its place.
(I work for the world's largest maker of tankless heaters, so it makes good sense, not that it wouldn't anyway! ;) )

Okay, the real issue: We recently tried to install a new dishwasher, and found one of the hot water angle stops all rotted when we tried to connect to it. It is only about 15 yrs old. Upon calling in a plumber, he tells us that ALL of them are bad and that the cause was the lack of dielectrics on the gas fired 40 gallon tank that has been in since maybe 1982 also. He installed a set of unions and replaced all valves including even the front main water shut off valve which was apparently bad also!

Does this sound right to you? I am not really doubting that the valves went bad, but I have never heard of the copper to galvanized connection "poisoning" the entire system like he said this did.

Lastly, I am a bit confused with your post above. You say that you come out of the heaters with 3/4 male copper adapters. How can you do that when the top of the heater has 3/4 galvanized pipe coming out?

Also, in another post you say that dielectrics are "good insurance" and even quote "Hammerzone" in your post. Yet you later state that you don't use them in new construction. I'm not trying to cause any trouble, just a bit confused. :confused:

Thanks for your patience with this long post,
Tom

plumberjames83 · Nov 12, 2007, 06:03 PM

My take:

New constrution uses all copper orl pex or al of one thing. They don't mix metals. Where as in your house they are going from galvenized to copper.

As for dielectirc unions and where to use them
Internattional plumbing code states:

650.23.1 Copper or copper-alloy tubing to galvanized steal pipe
Joints between copper or copper-alloy pipe to galvanized stell pipe shall be made with a brass fittingor dielectirc fitting. The coipper tubing shall be solderd to the fittingina na approved manner, and the fitting shall be screawed to the threaded pipe.

That's basic ly telling you where you have to use them and in what manner.
As for water heaters and their nipples. That is somethinf that most inpectors don't make us do . There has been debate here in Alabama as to wheater the copper fittings themselves. Acutally contain enough brass in them to make them conut as a brass fitting. But in new houses or apartments around here you won't find them (dielectric unions)
Only in remodels and repair jobs

ballengerb1 · Nov 12, 2007, 07:16 PM

Tankless Tom, I have question since you say you work for the largest tankless manufacturer, so who do you work for? I am asking because a recent recall of 199,000btu gas models covered about 5 brands and all were coming from the same manufacturer oversees in Japan. You original question was about unions and when copper and galvanized pipe get togetehr they make a small electric current via galvanic reaction. It takes years but it can eat the chrome off a trailer hitch. However, the worst wear is right at the connectionbetween the two metals. I have not seen how it attacks the angle stop cock which are frequently brass. Never thought they would become the problem, the pipes would blow first.

iamgrowler · Nov 12, 2007, 08:45 PM

Originally Posted by Tankless Tom

Does this sound right to you? I am not really doubting that the valves went bad, but I have never heard of the copper to galvanized connection "poisoning" the entire system like he said this did.

Sounds like you've been had.

Lastly, I am a bit confused with your post above. You say that you come out of the heaters with 3/4 male copper adapters. How can you do that when the top of the heater has 3/4 galvanized pipe coming out?

I'm not sure who you're addressing here, but you should never come directly out of the tank with copper male adapters.

If the tank has galvanized nipples you should take off from the top of those with brass or stainless nutted flexible connectors or dialectric unions.

If the tank arrives sans nipples, you should install either galvanized dialectric nipples or brass nipples and follow the paragraph above.

Also, in another post you say that dielectrics are "good insurance" and even quote "Hammerzone" in your post. Yet you later state that you don't use them in new construction. I'm not trying to cause any trouble, just a bit confused.

Still not sure who you're addressing here, but the bottom line is that you should never hook up a H/W Tank without some form of union at the top of the tank -- The union can be a flexible connector, a dialectric union or a brass union, but it should never be a copper male adapter.

iamgrowler · Nov 12, 2007, 08:53 PM

Tankless Tom, I have question since you say you work for the largest tankless manufacturer, so who do you work for? I am asking because a recent recall of 199,000btu gas models covered about 5 brands and all were coming from the same manufacturer oversees in Japan.

That was actually a defect in how the units were packed for shipping, not in the original construction of the unit.

Tankless Tom · Nov 12, 2007, 09:18 PM

Plumber James:
Thanks for your input. I understand what you are saying about using all copper or all PEX in all of the piping and fittings in new construction. What I still don't understand is as you say, some inspectors and most plumbers don't worry about installing dielectrics on a water heater WHEN I HAVE NEVER SEEN A WATER HEATER WITH COPPER NIPPLES. I'm not yelling here, just trying to emphasize my point regarding the junction between galvanized and copper on most houses. Even "Speedball Tom" says that he doesn't always install them, yet we have a plumber out here in Southern California telling us that ALL of the Angle Stops (Hot and Cold) in a large house have fallen apart due to the corrosion caused by not having dielectrics on the water heater! Is this possible?

"ballengerb1"
Thanks for your input also. Yes I can agree that the electrochemical reaction could be so strong as to "eat" (although there is often another term used here) the chrome off a trailer hitch, but one would think that the "eating" would have to be taking place on the hitch ball itself, right? Some of these valves were 40-50 feet away! :eek:

There should be no current flow between a copper pipe and the brass valve that is attached to it, (far from the hot water tank) and the corrosion that forms at the joint between the galvanized steel and the copper, which is above the tank, you would think, would stay right there, wouldn't it? :confused:

Do either of you suppose that it could have been caused by hard water? If not, then I'm going to take "Speedball's advice to another person who asked about dielectrics, and install them as "a good insurance policy". Sounds like maybe there are a lot of new construction homes out there that may have their valves and fixtures corroding away in 15 or 20 years, ya think? :o

I hope to hear from "Speedball" on my original question to him.
Thanks, Gentlemen

Oh sorry, ballengerb1,

About the Tankless: I work for Rinnai in California. And no, we haven't have any recall on our heaters, nor have we manufactured them for any other company who may have. Do you recall what the recall was for?

Tankless Tom · Nov 12, 2007, 09:23 PM

He "knows his stuff" and he knows how to clearly state it.

Tankless Tom · Nov 12, 2007, 09:44 PM

Originally Posted by iamgrowler

That was actually a defect in how the units were packed for shipping, not in the original construction of the unit.

Thanks for the info Growler, not only on the recall, but mainly on the proper way to hook up to a tank.

Yes, I had originally installed the tank about 25 years ago, (yup, 25 years! It didn't have to work very hard because it was being fed with solar hot water). I believe I am the one who plumbed it with two copper flex lines, which as you know have brass nuts on the end. I didn't see the condition of the connections before the plumber replaced them with dielectrics for my brother and sister.

Yeah, I think that "we (my baby sister) been had" also. I only wish I had been there when (or even before) this all took place.

The person I "was talking to" hopefully was "Speedball Tom", "Expert plumber". I got his information by entering the search terms "Dielectric unions" under "Plumbing". Please look at the 2nd and 10th entries and you will see what he is saying about male adapters, etc. It doesn't make any sense to me.

Thanks Again Growler,

Tankless Tom :D

Tankless Tom · Nov 12, 2007, 09:46 PM

You understood what I was asking and you told me what you have experienced.

speedball1 · Nov 13, 2007, 07:42 AM

The person I "was talking to" hopefully was "Speedball Tom",

Sorry tankless, this is my first time on this thread. Did you confuse me with Plumber James?

Even "Speedball Tom" says that he doesn't always install them, yet we have a plumber out here in Southern California telling us that ALL of the Angle Stops (Hot and Cold) in a large house have fallen apart due to the corrosion caused by not having dielectrics on the water heater! Is this possible?

Growler sez." you should never come directly out of the tank with copper male adapters."( Growler, like plumbing codes, will always err on the side of caution, and who's to say that's bad?)
Or what? All the angle stops will fall apart? Come on! While I agree that dielectrics are great insurance against electrolysis, yet in all of the hundreds of condos and single family homes we have never had a complaint or call back because we came out of the tank with 3'4" copper male adapters.
Like growler I think your plumber's blowing smoke up your skirt. Electrolysis will cause pinholes in your copper pipe but this is the first time in over 50years out in the field that I've ever heard of it selectively attacking all your angle stops. Something smells fishy here and I think it's your plumber. Cheers, Tom

labman · Nov 13, 2007, 08:00 AM

Speedball, I hope you are right. My church paid professional plumbers to install a 60 gallon commercial hot water tank. They came out of the tank with 1'' dielectric nipples, then a galvanized reducing coupling and copper male adapters.

As I think about it, it may have been a good application for a tankless heater, with the long periods of nobody using any water. We may only use very much hot water a dozen times a year when we fire up the dishwasher after a big dinner.

speedball1 · Nov 13, 2007, 08:13 AM

They came out of the tank with 1'' dielectric nipples, then a galvanized reducing coupling and copper male adapters.

Let me see! They installed a delectreic nipple so the copper wouldn't connect to the iron tank and then installed a galvanized reducer coupled to a copper adapter? Some how that would seem to cancel out the nipples. Let me repeat! "in all of the hundreds of condos and single family homes we have never had a complaint or call back because we came outta the tank with 3'4" copper male adapters."
That's not to say growler's not correct. ( Since he goes by the book he usually is) but I'm telling you how we do it in my corner of the world. Regards, Tom

iamgrowler · Nov 13, 2007, 08:55 AM

Originally Posted by Tankless Tom

Sounds like maybe there are a lot of new construction homes out there that may have their valves and fixtures corroding away in 15 or 20 years, ya think? :o

Depending on the acidity/alkalinity of the water source, the issue could manifest itself much, much sooner -- I've seen electrolysis take place with catastrophic results within two years on well water supplied systems.

Tankless Tom · Nov 13, 2007, 11:00 AM

So Growler, Let me see if I understand and can kind of sum this up.

Valves or other plumbing fixtures can corrode from water that is too acidic or alkaline, (in our case, "city water" (San Clemente, CA) which I am told is a mixture of aquifer and California aqueduct water.

The fact that the water heater had copper flex lines attached to gal. nipples probably had little or nothing to do with any "supposed" rotted or "poisioned" angle stops. There may have been some bad valves in the house, but they were probably bad due to age and water conditions.

Does this sound like a fairly accurate summary?

I was asking "Speedball Tom" earlier, about how he would use 3/4" male adapters. I was assuming that there would be male galv. nipples on the heaters. I guess these guys are using heaters with female holes and just screwing in the male coppers? "Quick and dirty" I guess, but if they are working fine, why not?

TT

labman · Nov 13, 2007, 11:29 AM

On something expensive with a warranty, it might be best to install exactly as the directions call for. Except for the dielectric unions also meant to stop convection currents, I don't see that they would hurt much. Those wouldn't make much sense on a tankless heater, so if your tank included them, I would expect them to be the plain ones.

iamgrowler · Nov 13, 2007, 05:48 PM

Originally Posted by Tankless Tom

So Growler, Let me see if I understand and can kind of sum this up.

Valves or other plumbing fixtures can corrode from water that is too acidic or alkaline, (in our case, "city water" (San Clemente, CA) which I am told is a mixture of aquifer and California aqueduct water.

No, I meant that acidic water is the catalyst that begins the action of electrolysis when two dissimilar metals are joined, steel and copper in this case.

The fact that the water heater had copper flex lines attached to gal. nipples probably had little or nothing to do with any "supposed" rotted or "poisioned" angle stops.

I wouldn't think so -- Then again, brass angle stops and other brass valves are manufactured from an amalgam of copper and zinc -- And bronze, which is also used for the same purposes, is an amalgam of copper and tin.

There may have been some bad valves in the house, but they were probably bad due to age and water conditions.

Does this sound like a fairly accurate summary?

There may also have been some level of electrolysis at work in these locations, particularly if the water source is highly acidic -- I've encountered a number of brass angle stops over the years that had literally rotted away the threads on galvanized nipples.

iamgrowler · Nov 13, 2007, 05:53 PM

Originally Posted by labman

On something expensive with a warranty, it might be best to install exactly as the directions call for. Except for the dielectric unions also meant to stop convection currents, I don't see that they would hurt much. Those wouldn't make much sense on a tankless heater, so if your tank included them, I would expect them to be the plain ones.

The Rinnai's have brass inlets and outlets, but I still use dielectric unions when installing them to make them easier to service.