AO Smith Ultra Low NOx Water Heater - Anode

[imacmill]

Hi folks,
I'm new here, but have been a DIY'er for a long time. I have a six year old AO Smith GCNH 40 200 water heater and I am recently getting a fair bit of corrosion material from my hot water faucets. I figured it's my anode. My problem is that I can't find where the anode is, and the manual isn't super clear. Attached are some pics and below is a link to the manual.

Anyone have experience with this model or similar? Is the anode under the hot water outlet? I removed the nipple to the hot water outlet, and I can't find an obvious next step. Is it under the T&P valve? I hope not because that looks like a pain to remove and replace.

Manual - https://www.hotwater.com/lit/im/res_gas/186221.pdf

Thanks,
Ian

 

[Fitter30]

https://www.hotwater.com/support/GCNH-40/
Click on parts list #7

 

[Sponsor]

 

[Reach4]

Is the anode under the hot water outlet? I removed the nipple to the hot water outlet, and I can't find an obvious next step. Is it under the T&P valve?

I am surprised you did not find it when you pulled that hot-side nipple.

 

[imacmill]

https://www.hotwater.com/support/GCNH-40/
Click on parts list #7

Thanks for replying. That looks similar to my manual, but I can't quite tell where the anode is supposed to be. Under the T&P valve or under the hot water outlet? If it is under the 'alternate' location, I'd think that is the circular tab just left of my vent in the 2nd pic from my post. But I would need to cut it open, which seems odd. I am not even sure how I would cut that hole open. Thoughts?

 

[imacmill]

I am surprised you did not find it when you pulled that hot-side nipple.

Me too. Is it somehow buried down in there?

 

[imacmill]

Me too. Is it somehow buried down in there?

Just for completeness, here is a pic of my hot water outlet nipple.

 

[Reach4]

Me too. Is it somehow buried down in there?

I have never done it. Can you hook something, and pull it up?

 

[imacmill]

I have never done it. Can you hook something, and pull it up?

I reached down in there with a wire hook about a foot and I didn't feel anything there. However I did wave it around in the tank, and I am pretty sure I can feel it beneath the 'alternate' location mentioned above. There is something vertical there and it is different than the flue. Which gets back to an earlier question. What is the best way to open up the top? Drill a hole, then metal snips? Do I risk damaging anything by doing that?

 

[Reach4]

I reached down in there with a wire hook about a foot and I didn't feel anything there. However I did wave it around in the tank, and I am pretty sure I can feel it beneath the 'alternate' location mentioned above. There is something vertical there and it is different than the flue. Which gets back to an earlier question. What is the best way to open up the top? Drill a hole, then metal snips? Do I risk damaging anything by doing that?

I think you will need to ride out this WH without a new anode, and hope to find an accessible hex head on your next.

Maybe power flush your WH periodically. See https://terrylove.com/forums/index....o-flush-a-hot-water-heater.79444/#post-576623 post #7.

EDIT: How about replacing that nipple with a combo anode?

 

[imacmill]

I think you will need to ride out this WH without a new anode, and hope to find an accessible hex head on your next.

Maybe power flush your WH periodically. See https://terrylove.com/forums/index....o-flush-a-hot-water-heater.79444/#post-576623 post #7.

EDIT: How about replacing that nipple with a combo anode?

Just following up on this thread. I have tried two different anode/hot water nipple combos. It seemed like a really promising suggestion. No luck though. The hot water opening on the water heater is maybe 1/32" greater than 3/4". The anodes are 3/4" which is fine, but the plastic outlet connecter between the nipple and anode is always wider than 3/4" (typically about 13/16" or 7/8"), so it doesn't fit. I tried some love taps to 'make it fit', but it seems like the amount of force needed to get it in will damage the water heater.

Aargh. I am not thrilled about needing to replace a 6-year old water heater that seems to be in good condition otherwise, but I don't see any other options at this point. Maybe I can regularly flush it for a few months to tide me over. Planned obsolescence is pretty annoying.

I do appreciate earlier help on this though.

 

[Reach4]

ust following up on this thread. I have tried two different anode/hot water nipple combos. It seemed like a really promising suggestion. No luck though. The hot water opening on the water heater is maybe 1/32" greater than 3/4". The anodes are 3/4" which is fine, but the plastic outlet connecter between the nipple and anode is always wider than 3/4" (typically about 13/16" or 7/8"), so it doesn't fit. I tried some love taps to 'make it fit', but it seems like the amount of force needed to get it in will damage the water heater.

When we say there is a 3/4 inch NPT thread for an anode or WH nipple, 3/4 is the nominal (what we call it) size. The actual pipe thread diameter is bigger. The wide part of the nipple that is between threads is 1.05 inch diameter.

If you are saying that you are trying to go through a plastic hole that is too small, you may have to pry out a plastic bushing, or you may have to cut some plastic.

 

[imacmill]

Sorry, I probably wasn't clear. The opening on the water heater is all metal (threads and opening below the threads). The problematic part is the metal opening below the threads that is just a hair wider than 3/4". The nipple is 1 & 1/16" outer diameter which is correct and matches the threads on the water heater.

The issue is the white plastic between the aluminum anode and the metal nipple (I don't know what that part is called) is wider than the anode, and wider than the opening. You can see an example here:
https://www.amazon.com/Bradford-White-Anode-Alum-nipple/dp/B016PF2KME