Hi all, will flexible anode rods not last as long as regular straight not flexible rods? I’m wondering specifically about the links in between the flexible anode rods since they are much thinner than the rod itself. Is there something that keeps the links from not rusting along with the rod? Thanks
Flexible anode rod links
- Thread starter acer925
- Start date
Users who are viewing this thread
The flex part, which may be stainless steel, does not contribute protection, but the the other part could be made thicker to compensate.
Sponsor
Paid Advertisement
Are you saying the flex part doesn’t rust? I was just concerned the flex a node rod wouldn’t be as good as the straight piece rod.
Jadnashua
Retired Defense Industry Engineer xxx
It depends on how much actual volume there is in the rod. A straight rod, installed at the factory, could go nearly to the bottom of the tank. A replacement rod may not. There's a limit on how big in diameter it can be to fit inside, but that could differ, too. A replacement rod COULD have more volume than what was in it. Note, on some WH with longer warranties, can come with two rods, and if there's a port, that might be a useful way to add more to one that did not come with two.
Some say stainless steel. Some don't.
If you have the overhead clearance for a straight one, go that route. The reason for a flex one is overhead clearance.
Do you get H2S (sulfur) smell from your hot water?
No sulfur smell, it’s just the original anode from 8.5 years ago. There’s not enough clearance above water heater to install a 44” anode. The factory one that’s in there now is 50”. I could have someone disconnect the entire heater for straight anode rod install but then labor charge skyrockets. Another option would be cutting a hole in my ceiling (into attic) and pulling it through. But if the flex anode is just as good as the regular one obviously it’d make sense just to go with that since it’s easier. I just didn’t like how the links were so thin, but maybe I can find one that specified stainless steel for the links as stainless doesn’t rust.
I think I was mistaken. There had been a review for Rheem Protech SP8371B that said it had stainless steel cables, but I don't find things to back it up. I do like that that model has a 0.9 inch diameter rod.
The cables carry very little current. Even if they are steel, they would not rust through.
You know that the great majority of people never change an anode rod -- they just get new heaters.
The reason I asked about the smell is that I have a powered anode with an adjustable length anode. It does not react with sulfur bacteria to turn sulfate into H2S like sacrificial anodes. However it costs a lot more than a sacrificial anode, so without the H2S consideration, it would be expensive. There are cheaper powered anodes with stubby electrodes, but I think the length is important, especially for a tall WH.
Last edited:
I ended up going with this one...https://www.amazon.com/Magnesium-Pr...-Applied+Thread+Sealant&qid=1602685615&sr=8-5
I don’t like the idea of an electric powered anode, I feel like I’d worry about it failing in some way. Only thing I don’t like is I’m going from a 50” to 44” anode, and my tank is 57” tall..am I getting too short of an anode rod?
I would rather go with one that is bigger in diameter, because it will have more anode material. The amount of material varies with more than than the square of the diameter of the element, if we presume a same-size core. Thus a 0.9 diameter anode would have 44% or more anode material than a 0.75 diameter anode.
The one you selected does say it has stainless steel connecting segments.
Sacrificial anodes are easy to cut to length with a hacksaw.
Take a picture of the old one, if you are successful at getting it out. Just curious.
But the diameter can’t be bigger than the hole right? The old anode has diameter 3/4” so that’s what I picked for the new one. But I’m going from 50” length to 44” length in a 57” tall, 50 gallon tank. It does say it can be used for 30-80 gallon tank. But wasn’t sure if it sitting 13” off the bottom mattered. I’ll take picture of old one.
A 3/4 inch pipe is 1.050 OD. When threaded to receive such a pipe, the thread is tapered, but the female hole will still pass 0.9 inches. It's close.
I don't know how much you give up being 13 inches off of the bottom. You are going to get more protection than those who never change an anode.
Some people remove the anode when the WH is new (for H2S reasons), and insert a plug. I would not do that.
Jadnashua
Retired Defense Industry Engineer xxx
A longer anode just provides a longer service life, not changes its effectiveness while it still exists. IOW, the more material it can sacrifice, the longer it can work. The actual surface area isn't the determining factor about effectiveness, less mass, gets sacrificed sooner.
You are mistaken. Your introspection was not sufficient for this IMO.
You have me a little nervous thinking what I ordered won’t fit. The one that’s in there now has 3/4” “diameter” as listed by manufacturer..so I ordered one with same diameter 3/4”. I’m thinking that’s the largest one I could’ve gotten.
3/4 is 0.75 inch. It will fit into the hole.
0.90 inch would have fit into the hole.
wait how would a 0.90” fit?
nevermind I get it..the inside diameter of npt is 0.75” so the outside is 1.05” which would fit a 0.90” anode.
Close enough. Right concept, but 0.9 is close due to thread depth and taper. The tap drill size for 3/4 NTP is 59/64, if that means something to you.
When you put the new anode in, the torque does not need to be anywhere as tight as you had to use to remove the old anode. I presume you have checked that you have a hex head for the anode. Some WHs put the anode under the hot nipple.
yes mine is hex head. I canceled the 44” and went with this wider/longer anode since I have 57” height.
https://www.homedepot.com/p/Rheem-P...n.+by+0.9+in.+diameter+flexible+magnesium}:qu
Jadnashua
Retired Defense Industry Engineer xxx
Over its useful lifetime, a sacrificial anode literally 'sacrifices' itself, and essentially dissolves. The more volume you have, the longer it can last. WH with a longer lifetime warranty tend to come with two anodes to provide more volume that can be sacrificed before they do not provide any benefit anymore. The reaction attacks the sacrificial anode because of its properties rather than the iron in the steel, protecting it in the process. Some tanks come with a second port, but it is just plugged. It won't hurt to add a second anode there, but it may be pretty corroded if you don't do it when new. Some designs will allow you to put a second one on the inlet port.
FWIW, over softened water can eat up a sacrificial anode in less than a year, so that should be checked if you have a softener.
FWIW, over softened water can eat up a sacrificial anode in less than a year, so that should be checked if you have a softener.
Similar threads
