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Corroded Pipe on Water Heater

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newinnj
newinnj Member Posts: 37
I have two pictures. First picture is a corroded pipe on a gas water heater. What is the root cause (different metals and bad installation?). Second picture is the solution and is that piped correctly. I appreciate the help.



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  • Ironman
    Ironman Member Posts: 7,400
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    It looks like the flux wasn't wiped off when it was soldered.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    newinnj
  • newinnj
    newinnj Member Posts: 37
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    Thanks. How does the new piping look?
  • hot_rod
    hot_rod Member Posts: 22,505
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    What is the ground wire for?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • newinnj
    newinnj Member Posts: 37
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    Ok its time to explain. I live in 3unit walkup. Top unit water heater went and they had it replaced. Water in top unit and middle unit. Five years later the pipe corroded last week. Water on all floor and units. I have only the pics. I figured there was an installation issue. Did mention to get a professional to do the recent work. I don't have an answer on the ground wire. It should be a power vented unit.
  • EzzyT
    EzzyT Member Posts: 1,297
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    @hot_rod in NJ as per the plumbing & electrical codes it is required to have the hot water heater water piping to be Bonded.
    E-Travis Mechanical LLC
    Etravismechanical@gmail.com
    201-887-8856
    newinnj
  • hot_rod
    hot_rod Member Posts: 22,505
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    EzzyT said:

    @hot_rod in NJ as per the plumbing & electrical codes it is required to have the hot water heater water piping to be Bonded.

    Is bonding the same as grounding? I thought that grounding was found to be a cause of copper tube failures?

    https://hansontank.com/straycurrent/
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • HVACNUT
    HVACNUT Member Posts: 5,894
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    The first pic looks like too much tape and was only on 3 or 4 threads.
  • Jamie Hall
    Jamie Hall Member Posts: 23,675
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    hot_rod said:

    EzzyT said:

    @hot_rod in NJ as per the plumbing & electrical codes it is required to have the hot water heater water piping to be Bonded.

    Is bonding the same as grounding? I thought that grounding was found to be a cause of copper tube failures?

    https://hansontank.com/straycurrent/
    @hot_rod -- a bit wordy, but take a look at this: http://www.differencebetween.net/science/difference-between-bonding-and-grounding/
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JUGHNE
    JUGHNE Member Posts: 11,111
    edited May 2020
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    This has always caused confusion.
    You Ground the electric neutral in the main CB panel to any number of electrodes; ground rods....metallic water UG service... steel frame of buildings with buried concrete footings.... and in recent years a "Ufer" grounding electrode is required in new buildings. This is made by having at least 10' of rebar in the footing connected to the grounding system. The weight of the building on the footing in contact with the earth is what gives this it's properties. And then you can tie them all together at some common point.
    The water line is by far the best ground electrode possible as you may have miles of iron pipe with copper water services.
    As plastic has come alone, then the "Ufer" is the next best thing.

    You then Bond all metallic piping, ductwork to the grounding system. This is to keep those items from becoming hot should any bare conductor come in contact with it. Bonding wires can be smaller than the grounding wire, they are based on the largest wire that may come in contact with those objects.
    This has become important with a plastic water service feeding interior copper water lines.

    A grounding system would pass no current under ideal systems.
    But if you lose your good solid neutral connection then anything could become "hot" as the electricity is looking for a return path to the source. Could be a person standing on concrete floor touching the furnace for instance.

    Grounding is like a "Having a gun in Texas....you don't need it often....but when you need it... you need it bad". :o
  • Paul Pollets
    Paul Pollets Member Posts: 3,658
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    Where's the union?
  • ratio
    ratio Member Posts: 3,702
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    Where's the union?

    Shark bite valve.
  • mattmia2
    mattmia2 Member Posts: 9,981
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    JUGHNE said:


    The water line is by far the best ground electrode possible as you may have miles of iron pipe with copper water services.
    As plastic has come alone, then the "Ufer" is the next best thing.

    Not only does it tie to the metallic piping in contact with the ground, it also bonds to all of your neighbors' electrical services which are bonded to the neutral so if there is a bad neutral in your service it will follow that path through your neighbors to the transformer at the pole.
  • JUGHNE
    JUGHNE Member Posts: 11,111
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    Also the primary side of the transformer, often 7200 VAC from hot to ground, shares the neutral with the safety ground.....it is the same wire in most cases.

    So if there is a not so good connection at the transformer neutral and the primary neutral/ground, the return of that transformer goes down to a ground rod, thru the soil looking for a better connection back to the substation....this is why care should be taken when removing the jumper on the water meter. There could be a high potential of voltage available when the jumper is removed.
    This is the same surprise you get when you have hold of that innocent white wire when something is energized.

    This is more common in rural areas out here. Each farmstead may have one transformer fed by miles of primary wire.
    Each pole (could be 12-14 poles per mile) has a ground rod connected to the primary neutral side. If there is a loose neutral/ground connection on the neighbor's farm then some current may travel thru the earth as stray voltage.

    This is most noticeable when the cows will not go into the dairy barn with the wet concrete floor and all the equipment is bonded to the electrical service ground. Dairy cows are very sensitive to small amounts of stray voltage. I could feel it with wet feet and wet hands, especially with a cut finger.
    I went thru this on a new barn, lost a lot of time and lawyers were involved.

    I run bonding wires from all piping set in the concrete to the service ground. This lessened the voltage but the cows could still feel it.
    Eventually the power company found loose connections miles away.

    Today you build a grounded electrode ramp of concrete that gradually changes the potential between dirt earth and the barn concrete. I did only one, don't know if it was needed, but you have only chance to install it. The knucklehead farmer thought it was all phooey but would have thought otherwise if he had problems. (lawyers again possible).
    STEVEusaPA
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,391
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    Hi @newinnj , About why the leak happened in the first place; the copper pipe was screwed directly to a plastic lined steel nipple. The steel rusted to protect the copper. In California, I'd use a copper or stainless flex connector directly to the lined nipple as long as the connector had a true dielectric built in. That arrangement has worked well for me for a long time. With that in place, you definitely want the hot and cold lined bonded together so there is no reason for current to try and flow through the water heater.

    Yours, Larry
    newinnj
  • Jamie Hall
    Jamie Hall Member Posts: 23,675
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    If you think cows are sensitive, try horses. Wooden floors (2 inch oak) have a lot to be said for them! On the other hand, it's why electric fences work...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,849
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    @JUGHNE 's explanation of grounding and bonding is spot on.

    I will also add that we have (for the last 30 years or so) put a jumper around the water meter. The code requires the interior metal piping to be bonded and with the advent of plastic water meters a jumper is required around all meters.

    In a summer camp with a well where the water pump is disconnected in the winter a jumper around the pump is a good idea.

    Same for water heaters a jumper around the water heater keeps the hot water piping bonded and may reduce any stray current from flowing through the hot water tank.

    As for the picture problems with dielectric unions and nipples are common.