Rheem hybrid with rusted nipple

The Tank Rheem hybrid with rusted nipple

  • This topic has 3 replies, 1 voice, and was last updated 4 years ago by Rand.
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  • #23838

    First post here, I’d appreciate any helpful information that leads me to a successful outcome.

    I have a 50gallon rheem hybrid electric that came with the house.
    Model? AP15121?
    link to manual

    It is aprox 5 years old, warranty started in 5/2013 with home purchase(1953 house)
    Fairly good with DIY, work on cars etc.. not too knowledgeable about hot water heaters or plumbing beyond very basics.

    The dielectric union on the cold water intake appears failed. Extremely rusty nipple going into the tank.

    What is the best way to fix? Ideas? Protips?

    I was considering replacing the union with threaded brass but of course the nipple needs replaced also… are these threadlockered in? Removal tips?

    The pipe is quite rusted to the point of leaving rust “sand” on the floor. I am not confident of not shredding it when trying to remove.

    I do have access to most tools including impact.

    The only copper in the house is the 6ft piece going from the tank to the ceiling.. everything else is pex.. house was plundered of copper while vacant before I purchased.

    Final note: Everything was sorta hillbilly installed.. deck railing, roof, this hot water tank, everything works but maybe not quite installed the right way.

    For example the condensate lines lead into a wall then a sewer drain.. whereas the instruction manual calls for draining into an open drain, no sewer or closed drains.

    Attached is a picture of the issue.

    Oddly enough the hot water outlet is pristine.

    Attached files

    Randy Schuyler

    This is a classic case of so-called “dielectric union” failure. Naturally, the union has to go. The nipple may not be as bad as it looks. Most nipples these days are PEX- or plastic-lined, so it probably isn’t rusted clear through. If you drop a 5/8-inch hex bolt into it, that will help it keep its shape while you remove it. That will probably require a pipe wrench, cheater bar and brute force.

    Randy Schuyler

    PS — Don’t forget to check the sacrificial anode when the tank hits six years.

    Larry Weingarten

    Hello, That looks pretty unhappy to me. I think I’d cut the copper line and solder a male adapter to it a little ways back from the tank. I’d remove both union and nipple. If they come apart then use Randy’s trick with the bolt. Install new lined nipple and put a copper or stainless flex connector between the nipple and male adapter. 😎

    Might be good to turn off the water first! 😀

    Yours, Larry


    Definitely going to fully drain the tank as much as possible its installed without a drain pan… on short cinder blocks.
    but a hose then a few towels and a shop vac will hopefully cut down the mess.

    I have heard of a few tricks such as
    tightening the union to unscrew the nipple, putting a pipe cap on,
    or even pinning it with a drilled pipe cap and a pin.

    Any idea if those work? I dont even know which way the threads are yet.. because once I start this I HAVE to finish it.. want to be fully prepared with tools and ideas ahead of time.

    I have quite a few automotive tools.. not too many big pipe wrench type though.

    Appreciate the advice fellas.


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