Dark Rust on Water Intake Connection to Expansion Tank

Discussion in 'Water Heater Forum, Tanks' started by Robert98, May 23, 2020 at 11:59 AM.

  1. Robert98

    Robert98 New Member

    Cary, NC
    Hey All,
    I was changing my expansion tank today and when I took it off it and the intake pipe were completely clogged with rust that looked black. The metal lip inside after the threading was completely rusted out at the bottom and the expansion tank connection was uneven from rust as well. My intake is comprised of several pieces mostly copper but it looks like there are steel pieces as well. There is also exterior corrosion on the outgoing pipe as shown. Is this a failure from insufficient teflon tape connecting the two pieces or was this a poor installation putting in steel pipe instead of all copper? I can manage for now as I cleaned and flushed out the existing loose rust but going forward should I replace the pipes or is this a common occurrance? Thanks 20200523_134936.jpg 20200523_135516.jpg 20200523_140248.jpg
  2. Reach4

    Reach4 Well-Known Member

    Sep 25, 2013
    On that middle picture could the stuff above the threads be sediment build-up, or are the threads rusted away too?

    On the top picture, can you grab that thing?

    On the bottom picture, I suspect a tiny leak that did not matter. Would more tape, better tape, more dope, better dope, or more turns have prevented this? I think so. The other two pictures look more alarming to me.

    I presume you changed the tank because it failed. What make and model was it, and when was it put in?
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  4. Robert98

    Robert98 New Member

    Cary, NC
    Actually I didn't change the tank I was just changing the expansion tank and anode to give it more life. (Haven't got to the anode yet) It's a whirlpool BFG1F5040T3Nov installed around 08-09 I believe and figure I would do some preventative maintenance.

    On the middle pic the threads are rusted away on the expansion tank but I am replacing anyway. On the top pic the lip is the metal backing after the threading and the open part is part that is rusted away. I pulled any loose rust out and ran water through it but am afraid it is too late to remedy. I may just leave it until I replace the water heater in probably a few years. Good to know about the bottom pic I won't worry about it now. I appreciate it.
  5. fitter30

    fitter30 Active Member

    Feb 2, 2020
    Retired service tech
    Peace valley missouri
    Looking at galvanized close and shoulder nipples the galvanizing isn't that great so go with brass.
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