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Old 06-06-2015, 07:29 PM   #1
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weeping sacrificial anode on water heater

When my rig was winterized a year ago I let a dealer do the winterization when I was in for warranty work and they yanked the anode rod and left it out with water sitting on the threads. In the spring the threads had corroded. I could get the old rod in but a replacement Camco rod would not fit due to the rusted threads. Now the old anode rod is wearing thin and I need to replace the the rod. I checked the threads at the base of both rods and they match up. The old rod has similar deterioration which is what allows it to seat but now it has started weeping water out of the threads and must be replaced. Ideally I would like to replace the fitting that goes into the tank but that doesn't appear to be possible. Has anyone dealt with deteriorated threads for the fitting that accepts their sacrificial anode and if so what was your fix? At this point it seems like I may have to replace the water heater to fix the issue.

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Old 06-06-2015, 07:42 PM   #2
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I would try this first.

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Old 06-06-2015, 07:59 PM   #3
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Try a small wire brush to clean threads, then when you put one back inuse some plumbers tape on new rod. We always use plumbers tape, easyiers to take put also.
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Old 06-06-2015, 08:04 PM   #4
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Ironic that I was just installing a new anode in my Surban WH a couple weeks ago and I think I had your same problem. I decided to purchase a $29 tap to clean the threads from hardware store which was a 3/4-14 NPT tap. I'm not sure if there are different thread options so take your old anode with you to purchase the correct size tap. Whatever you do don't force the tap in the water heaters 3/4 pipe thread hole with a ratchet/wench. Make sure you finger start it so it won't get cross threaded and then just turn it in a little at a time. The tap I have can accept a 3/4 socket with an extension so I used it to extend past the obsticals and made it easier to turn the tap without using much force. I was able to do most of the cleaning without using the socket handle and only used the ratchet to break the tap loose when I tried to go just a little too far. The lime and calcium deposits make it look like the threads are gone but the calcium and other minerals are probably just filling the threads. The minerals that you need to remove from threads is somewhat soft so go slow and backup often to clear threads of the tap. After you're done cleaning the threads connecting to city water will allow you to flush the tank to get any unwanted minerals out of the tank.
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Old 06-06-2015, 08:07 PM   #5
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It's 3/4" NPT. Borrow or buy a 3/4" pipe tap and chase the threads, just do not go too deep. Go slow and when you meet resistance, stop and back it out and look to see if the rust is gone. Also make sure you use Teflon tape on the anode.
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Old 06-07-2015, 12:28 PM   #6
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Happy guy,,,,I don't want to sound like I'm talking down to you,,,,but have you simply tried wrapping the threads on the rod with teflon or plumber's crayon before you go through all this?
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Old 06-07-2015, 12:39 PM   #7
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Happy guy

On your Suburban anode rod and drain. With 40 years of working on RVs I can tell you you will hardly ever pull a rod out with out the corrosion. Anytime iron or steel are married to aluminum you get corrosion. We always have to tap the threads to get a good firm grip. You will also notice there are only a few threads that hold it in place. Tapping the threads is one of our DEwinterizing points. Or yes you will get a wheel. If you don't have a tap ( expensive ) you may try Teflon tape, BUT do not over tighten and pull the threads.
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Old 06-07-2015, 04:15 PM   #8
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Please clarify your post......too much info run together!

To begin with, how old is the RV (specifically, how old is the HWH)?

If old enough, it sounds like the original plug and anode has been worn away (as intended to spare the electric element) and has begun to leak. No sense repairing that......wrapping it with nuckum putty or the's used up.

Are you trying to say that the newly purchased plug and anode will not even begin to thread into the hole? Have you shown a good light into it and examined the threads (how's your eye sight? If needed grab a magnifier)

Is your goal to get a new plug and rod into a somewhat corroded (though maybe filled with percipitated iron and calcium carbonate crud) hole?

Hey fellow forum guys.....if the new plug and anode has threads that appear undamaged upon close visual inspection......should Happy begin with a round wire brush that will fit through the opening into the water heater......and use either vinegar (or muratic acid) to see if he can't clean out any deposits that may be filling in the threads? Seems like leaving tap water laying on those treads would leave some rust staining, but this should not cause enough corrosion to destroy threads!!

If the threads are a little the worse for wear.......and Happy needs to chase the threads......doesn't that mean gently and slowly turnning a 3/4 inch NPT tap, held perfectly square to the hole, so as to run it through the existing threads to remove deposits, without truly cutting away any more metal? Does this explain "chasing threads" properly?

And lastly, if Happy removes some stock (metal shavings noted) and finds the new plug and rod now thread in (perhaps even seeming a little loosey-goosey) would he be best off by generously coating the threads with liquid teflon pipe joint sealer.....or should he wrap on a generous thickness of teflon tape...applied in counter-clockwise direction?

How old should the HWH be for him to call it "quits" and buy a new one....or should he get advice on over tapping the hole size and using some sort of thread repair sleeve?
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Old 06-07-2015, 06:34 PM   #9
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Happy guy

Your problem is Galvonic corrosion. Look it up on the net. It's the corrosion caused by the reaction of molecular movement of the steel being different than the movement of the aluminum. I know it sounds weird but it really is what causes the threads in the aluminum tank to get heavily corroded. Tap the threads gently and use a corrosion preventing paste when re inserting the rod. This is why you see plastic plugs in the other brand of RV water heater. Customers who have used pipe plugs in their tanks have ripped the threads right out.
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Old 06-07-2015, 07:37 PM   #10
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Picked up tap off Amazon around $20. Pull anode for the winter, clean threads with tap, back flush good with back flush tool. Let air dry a day or so, then put anode back in with Telfon tape. This part of the rig is ready to go, do not have to deal with rusty threads. Just have to fill and test before turning on electric.

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