Anode rod on Suburban water heater

[happyhiker]

Because I am new to the RV maintenance routine, I have just discovered that my Suburban water heater has an anode rod that is supposed to prevent the tank from corroding.  More specifically, the owner's manual to the water heater states that it needs to be replaced annually.  Well, I have never done this (going on 2 years), so I was just wondering if anyone had any experience doing this.  It looks a simple as removing a light bulb and replacing, but I searched the boards and couldn't find any threads on the topic.  I thought I would mention it, if for no other reason, that someone (like me) was simply unaware of this issue.


I am attaching page 7 of the manual for more specific information. This was the manual for the hot water heater that came with my DB 14. I have the Suburban SW6DE.

[attachment id="1373"]

[mitch]

It's as straight forward as it looks, I replaced mine this year.  Mine lasted 2 years.  Make sure you release the pressure from the tank!!! If you don't the thing will shoot out with a fair amount of force, enough to cause significant injury if you're in its way.

[happyhiker]

Thanks Mitch.  And, I have to say, I love Amazon.  Standard part, in stock, Prime, delivered to my door in 2 days.  

http://www.amazon.com/Suburban-232767-Water-Heater-Anode/dp/B003VAYRNM?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

[happykamper]

I too replace mine about every other year.

[gbpack]

We've only used ours for a total camping time of 6 weeks and it looks like it's about half used up (dissolved) already. Does that sound right?

[charliem]

[font size="3"]You guys got me thinking, so I went out and checked my anode. The CL was delivered new in Dec 2013 and used 2014 and 2015 camping seasons including two 6 week trips and many weekend+ trips. Overall about 25K miles. The OEM magnesium rod is showing deterioration, but no where near wear out. So I conclude it depends on usage and water type. Other sources including the Suburban factory manual suggest going to aluminum vs magnesium if wear seems excessive because aluminum is less reactive. My take is if the magnesium is degrading it's doing its job. I'd rather replace a mag rod more often than replace the WH in a few years. So check it each season and don't stay up at night worrying.

Camp on!
[/font]

[david]

We've only used ours for a total camping time of 6 weeks and it looks like it's about half used up (dissolved) already. Does that sound right?

[p]
[/p][p]That sounds way too fast.[/p][p]
[/p][p]Not to be too technical, but you may have a DC fault to the water system, possibly from your fresh water pump. A DC positive connected to water sets up an electrolysis system with the magnesium anode and quickly destroys it. I have seen this happen on boats when a live DC connection lays in the bilge water. The zinc anodes on the external metals: prop, rudder, etc. waste away in a few weeks, not many months as is normal.[/p][p]
[/p][p]What I would do is to replace the anode and then after you use your camper, disconnect the battery. That will eliminate DC leakage if that is the problem. Then if that extends the anode life you may want to investigate further.[/p][p]
[/p][p]David
[/p]

[ammobob]

[quote source="/post/20983/thread" author="@charliem" timestamp="1462383529"][font size="3"]You guys got me thinking, so I went out and checked my anode. The CL was delivered new in Dec 2013 and used 2014 and 2015 camping seasons including two 6 week trips and many weekend+ trips. Overall about 25K miles. The OEM magnesium rod is showing deterioration, but no where near wear out. So I conclude it depends on usage and water type. Other sources including the Suburban factory manual suggest going to aluminum vs magnesium if wear seems excessive because aluminum is less reactive. My take is if the magnesium is degrading it's doing its job. I'd rather replace a mag rod more often than replace the WH in a few years. So check it each season and don't stay up at night worrying.

Camp on!
[/font][/quote][p]Charliem is on the right path. I built water heaters for 4.5 years and the magnesium rod is doing it's job if it is deteriorating. Most residential water heaters have 3 to 4' rods designed to last longer usually 10-15 years. The little 6" rods in our campers are cheap and will generally deteriorate closer to the steel cap it's attached to. You should expect to replace them on average every 2 years or so. Aluminum is a better choice.[/p][p]
[/p][p]David may have a point also though I an not an electrician.
[/p]

[mitch]

[quote timestamp="1462382173" author="@gbpack" source="/post/20981/thread"]We've only used ours for a total camping time of 6 weeks and it looks like it's about half used up (dissolved) already. Does that sound right?



My experience mirrors that so yes, it sound right to me.[/quote]

[djsamuel]

Got my 21BHS in September 2013 and have over 100 nights in it.  Checked the anode a couple of months ago and found it about half gone.  Have another anode ready to go, but didn't change it.  I'll check it in the fall.

[charliem]

[quote source="/post/20987/thread" author="@ammobob" timestamp="1462387020"][p]Charliem is on the right path..................  Aluminum is a better choice.[/p][p]
[/p][p]
[/p][/quote][font size="3"]Bob,

Why do you think aluminum is a better choice for replacement? My reading indicates AL is less reactive, thus would last longer but not protect as well? Mg, although it must be replaced more often, might protect the tank better?

Your thoughts?

And it does seem that any problem we have, David has seen it on a boat somewhere. Great asset.
[/font]

[david]

Charlie:

You are correct. Magnesium is much more "reactive" than aluminum or zinc and will protect better but won't last as long. You can't go wrong with more protection, as long as you change them regularly. In boat usage, when they are 50% gone it is time to change them. I suspect the same is true in RV fresh water systems. By the time they are half gone they have built up an insulating layer that makes them less effective.

David

[djsamuel]

Charlie:

You are correct. Magnesium is much more "reactive" than aluminum or zinc and will protect better but won't last as long. You can't go wrong with more protection, as long as you change them regularly. In boat usage, when they are 50% gone it is time to change them. I suspect the same is true in RV fresh water systems. By the time they are half gone they have built up an insulating layer that makes them less effective.

David

Thanks David.  I never realized this.

[daplumbr]

I changed mine this spring even though it was overall about 75%. The problem was what Bob pointed out, the rod was almost all the way through near the cap. I didn't want it breaking off inside the water tank and if $15 and 5 minutes will prevent that, I'm in. 

[gbpack]

[quote timestamp="1462382173" author="@gbpack" source="/post/20981/thread"]We've only used ours for a total camping time of 6 weeks and it looks like it's about half used up (dissolved) already. Does that sound right?

[p]
[/p][p]That sounds way too fast.[/p][p]
[/p][p]Not to be too technical, but you may have a DC fault to the water system, possibly from your fresh water pump. A DC positive connected to water sets up an electrolysis system with the magnesium anode and quickly destroys it. I have seen this happen on boats when a live DC connection lays in the bilge water. The zinc anodes on the external metals: prop, rudder, etc. waste away in a few weeks, not many months as is normal.[/p][p]
[/p][p]What I would do is to replace the anode and then after you use your camper, disconnect the battery. That will eliminate DC leakage if that is the problem. Then if that extends the anode life you may want to investigate further.[/p][p]
[/p][p]David
[/p][/quote]

Thanks David. We will try that. I thought it was too soon (to be half used up) as well. FYI, we do turn off the battery when we get home from a trip (and a day after we arrive at a campsite with 110v hook-up). I will replace the anode and watch it closely. If the problem continues after that, I'll have it looked at. Thanks to all of you guys for your feedback!