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  1. #1
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    Default Dielectric Union or just rust/corrosion??

    I've personally never been able to wrap my pea-sized brain around the whole dielectric union on water heaters. I understand the "concepts", but....well I'm dense.

    So, please look at the photo and tell me if you think this is an issue pertaining to dielectric unions or rust. I'm seeing the plastic parts on the flexible copper pipes. I have no idea if there is a rubber or plastic gasket on the inside of the fitting.

    Disregard the other issues you'll see in the photos, I've written up the darn thing from top to bottom. They basically need a new water heater.

    I've just never grasped the dielectric concept in practical ways.

    Thanks in advance,
    Bruce

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  2. #2
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    Default Re: Dielectric Union or just rust/corrosion??

    A dielectric union is not needed as shown.
    The copper flex has brass connected to the galv pipe.

    As for the rust and corrosion, it may be that the WH and nipples are much older than the copper, as well as a leak at the shutoff.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  3. #3
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    Default Re: Dielectric Union or just rust/corrosion??

    Quote Originally Posted by Rick Cantrell View Post
    A dielectric union is not needed as shown.
    The copper flex has brass connected to the galv pipe.

    As for the rust and corrosion, it may be that the WH and nipples are much older than the copper, as well as a leak at the shutoff.
    Thank you. Hadn't thought of older nipples.

    Bruce Thompson, Lic. #9199
    www.TylerHomeInspector.com
    Home Inspections in the Tyler and East Texas area

  4. #4
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    Default Re: Dielectric Union or just rust/corrosion??

    Quote Originally Posted by Rick Cantrell View Post

    As for the rust and corrosion, .
    .
    Looks like Combustion Gas Spillage Damage.

    * water as a byproduct of combustion gas combined with other acidic waste byproducts spilling out the draft hood much like an Acid Fog .
    .

    Last edited by Billy Stephens; 02-15-2012 at 08:45 PM.
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  5. #5
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    Default Re: Dielectric Union or just rust/corrosion??

    Bruce,

    Rick is mistaken, that is NOT a Galvanized pipe nipple, it is a standard (sch. 40) 3/4" x 6" BLACK (steel or "iron") pipe right threaded (the "R")nipple, i.e. not for potable or water plumbing, commonly used for GAS piping.

    Beyond just what it looks like, it is labeled! UPC +"03033690379"

    That is a Beck Manufacturing A800-05-060-01, i.e. "A" finished product, 800=standard or Sch. 40, seemless steel, BLACK pipe, 05=3/4", 060=length, in this case 6", 01=black pipe (05 suffix would be galv).

    This is what you'd commonly find used with a cap under a black "iron" tee fitting as a sediment trap, or off a fitting as a stub to a gas valve, etc.

    It should not be used anywhere in the water supply plumbing system, esp. potable.

    Black steel ("iron") pipe is not galvanized, it is also NOT a "dielectric", which would be bronze or brass (not all of either is equal).

    There are myrad of formulae for steel, "iron", bronze & brass - they are not equal. Galvanized does not equal ungalvanized steel (or "iron") on the galvanic scale.

    Amongst the multitude of problems, the use of black pipe nipples in and of itself would corrode as shown when improperly installed upon a WH supply, or elsewhere in the potable system.

    Chlorinated water byproducts, aggressive water, heck water itself, completes the circuit for galvanic corrosion. The copper looping and in contact with aluminum tape on the vent, the backside of the collar, the top of the painted WH shell, products of combustion, including water vapor, and a host of other deficiencies contribute to accellerated deterioration. If the tank isn't leaking yet, its just a matter of time until the black steel and anode are completely sacrificed and the inner tank blows/fails/goes. Black steel in contact with galv threaded nipples to the inner tank likely also deteriorated.

    I've posted before the galvanic scale. The process is galvanic corrosion.

    BTW Beck Mfg. used to supply similar sized galv "conduit" nipples - for electric - not "pipe" and not for plumbing, IIRC they discontinued a couple of years ago (another common DIY purchase error at the supply stores - using sh.40 or 80 galv threaded "conduit" for plumbing "pipe".



    HTH.


  6. #6
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    Default Re: Dielectric Union or just rust/corrosion??

    Pls. excuse few typos above, such as "seemless" should be "seamless", etc.

    Doesn't matter that the flex or cor. copper has a brass nut, esp. when the cor. copper from the cold supply is or was in direct (side wall) contact with the improper black steel ("black iron") nipple on the hot outlet thus quick deterioration of the valve (direction?) as well (plus fatigue/heat, etc.).

    P.S. this is the pic I was referring to:



    Last edited by H.G. Watson, Sr.; 02-16-2012 at 10:37 AM.

  7. #7
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    Default Re: Dielectric Union or just rust/corrosion??

    Quote Originally Posted by H.G. Watson, Sr. View Post
    Bruce,

    Rick is mistaken, that is NOT a Galvanized pipe nipple, it is a standard (sch. 40) 3/4" x 6" BLACK (steel or "iron") pipe right threaded (the "R")nipple, i.e. not for potable or water plumbing, commonly used for GAS piping.

    Beyond just what it looks like, it is labeled! UPC +"03033690379"

    That is a Beck Manufacturing A800-05-060-01, i.e. "A" finished product, 800=standard or Sch. 40, seemless steel, BLACK pipe, 05=3/4", 060=length, in this case 6", 01=black pipe (05 suffix would be galv).

    This is what you'd commonly find used with a cap under a black "iron" tee fitting as a sediment trap, or off a fitting as a stub to a gas valve, etc.

    It should not be used anywhere in the water supply plumbing system, esp. potable.

    Black steel ("iron") pipe is not galvanized, it is also NOT a "dielectric", which would be bronze or brass (not all of either is equal).

    There are myrad of formulae for steel, "iron", bronze & brass - they are not equal. Galvanized does not equal ungalvanized steel (or "iron") on the galvanic scale.

    Amongst the multitude of problems, the use of black pipe nipples in and of itself would corrode as shown when improperly installed upon a WH supply, or elsewhere in the potable system.

    Chlorinated water byproducts, aggressive water, heck water itself, completes the circuit for galvanic corrosion. The copper looping and in contact with aluminum tape on the vent, the backside of the collar, the top of the painted WH shell, products of combustion, including water vapor, and a host of other deficiencies contribute to accellerated deterioration. If the tank isn't leaking yet, its just a matter of time until the black steel and anode are completely sacrificed and the inner tank blows/fails/goes. Black steel in contact with galv threaded nipples to the inner tank likely also deteriorated.

    I've posted before the galvanic scale. The process is galvanic corrosion.

    BTW Beck Mfg. used to supply similar sized galv "conduit" nipples - for electric - not "pipe" and not for plumbing, IIRC they discontinued a couple of years ago (another common DIY purchase error at the supply stores - using sh.40 or 80 galv threaded "conduit" for plumbing "pipe".
    HTH.
    Wow, you know the UPC codes! Thanks for information.

    Bruce

    Bruce Thompson, Lic. #9199
    www.TylerHomeInspector.com
    Home Inspections in the Tyler and East Texas area

  8. #8
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    Default Re: Dielectric Union or just rust/corrosion??

    Quote Originally Posted by H.G. Watson, Sr. View Post
    Bruce,

    Rick is mistaken, that is NOT a Galvanized pipe nipple, it is a standard (sch. 40) 3/4" x 6" BLACK...
    That could be why it's rusted so badly.

    ' correct a wise man and you gain a friend... correct a fool and he'll bloody your nose'.

  9. #9
    Join Date
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    Default Re: Dielectric Union or just rust/corrosion??


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