Corrosion of Alde Convectors

Tabaz

Thanks so much fstop and Ham!  We'll order five gallons to be safe.  BTW, does anyone really comprehend BrianZ's posts?  Asking for a friend.

fstop32

I think I understand what BrianZ was saying but I'll wait till he chimes in and then I'll reply "yep, that's exactly what I thought he was saying"! 

Tabaz

Fstop, you must be our ambassador to China. What a great response! 

DanWeitzel

DanWeitzel said:

Hi all. Just stumbled on this thread & have read thru all posts.  Went today to check my 2016 T@B and found some bulging on the top driver side connection of the rear convector.  Also felt but couldn't see a small bulge on the lower rear of the passenger side convector.  We purchased this T@B used November 2020 and I did the partial fluid change this spring.  At the same time in installed the anode rod and we did not use the Alde until this fall so there was no fluid circulation.  Interestingly you can see in the pic the degradation of the rod in just several months.  I've cleaned (sacrificial anode 4 pic after cleaning) & reinstalled the anode rod & will see what happens as we use the Alde for heating this winter (TX camper).  After reading these post I plan to drain & clean all convector connections & replace with new transfer fluid.  Until than I will keep tracking this thread for more suggestions. Also considering grounding all convectors electrically to the anode ground.  Any comments on that?

Here is an update to my above post.  After several more months with the anode installed I pulled it to check and again they showed corrosion and some buildup (see pics).  As an aside this corrosion buildup is very hard and difficult to remove.  Today a friend asked if he should purchase a magnesium or aluminum anode rod for his RV.  I was under the impression all anode rods were magnesium (?) and told him so.  I decided to check if this was true and found the Camco RV anode rods (which I used) are aluminum.  Now I am wondering if using these aluminum rods are the right thing to use in our Alde system?  Since the convectors are aluminum am I causing more issues than solving by using this aluminum anode rod?  For safety sake I plan to pull the aluminum rod until I get some feedback.  

DanWeitzel

Update to my last comment.  I reviewed my purchase history and I do in fact have a magnesium anode rod.  Still any comments on aluminum -vs- magnesium anodes & Alde fluid are appreciated.

BridgerSunset

@DanWeitzel
Wish I could point you to an exact "cause & effect" website explaining what you're seeing.

It appears to me to be related to a corrosion mechanism I admit I've never fully understood.  If you look into "oxygen differential" as it relates to corrosion of sacrificial anodes & liquids, I believe you can make a case that the metal loss on your anode is simply due to being submerged in a less-oxygenated environment adjacent to an oxygenated environment.   The solids may simply be the oxides formed from the underlying metal loss which occurs due to this oxygen difference.  I think it's a bit more sophisticated than what we know as "rusting", but in the same ballpark.  Why these deposits are more tenacious to remove than the previous, I can't say.

If the above is occurring, then the anode isn't really losing metal to, nor stealing metal from the rest of the Alde system. And I'm pretty sure the result would be the same for either Al or Mg anodes.

I have seen this kind of corrosion in steel pipe that is buried within both a disturbed & undisturbed soil -- presumably the oxygen & resistivity difference is what promotes external corrosion at the interface of the two soil types.

I've always had in the back of my mind that this same setup is partly at fault at those convector stubs, because of the potential to pull in oxygen there too, thus creating an oxygen-differential environment in an area where fluid is stagnant.

Just hoping that the more people investigate (like @DanWeitzel & others) that we'll get to the answer.

Tabulating

I have read a few comments mentioning how hard the heating connection clamps are to remove.  I bought these and they make removing the clamps easy. 

Knipex Spring Hose Clamp Pliers With retainer

It has pivoting crowns designed to engage the tabs on the clamp AND the lock automatically once you have the clamp expanded enough to undo the fitting.  I have an '18 400 that did not have the Alde Flow box, so I added it.  This pliers made removing and then reinstalling the clamps trivial.

They are $60 to $100 depending upon where you buy them, but a good tool is a joy forever and they made working on the Alde much more joyful.  Having used them, I wouldn't want work on the Tab heating without them.

Bill



I

Dutch061

I serviced the Alde yesterday in our 2020 400 BDL and changed to the Rhomar water. I detailed it in the post about switching to Rhomar. 

I wanted to add that as I was doing voltage drop testing, that the frame, 12 VDC, and the 120 VAC grounds are all tied together with less than .002 volts drop across them. However, when measuring between the Alde case and the negative post of the battery I found that the drop was over .040 volts. This doesn't sound like much. To take it to another level, I switched my measurement to Amps - milli-amps and was shocked to see that the same Alde case to negative battery cable had right at .125 amps draw.

This is more than sufficient to create galvanic action in this system and then some. Since there are dissimilar metals and a coolant that will conduct electricity. By installing a ground wire from the Alde case to a ground, this amperage draw went to zero. If by chance the coolant becomes slightly acidic, it is even a better battery. 

So, my official thoughts (although I haven't pondered it like I do most things) is that the root cause of the evil is galvanic action. The swapping of fluids is probably an effort to provide better corrosion protection overall. However, based on my measurements, if you are not checking or installing an auxiliary ground you are not fixing the root cause of the problem. I believe this is why the Airstream bulletin goes into great detail about adding a ground wire and replacing the main ground between the converter and the power distribution center.

Brad

[Deleted User]

Can your elevate your findings to NuCamp? 

bergger

I’m fairly handy when it comes to simple things But understanding electricity is something I just do not get. However I’m sure I’m capable of installing a ground if it is easy to do and explained to me.  So Dutch061, is it easy to do and if so is it something you could post in detail, parts needed and what goes where? Even with the corrosion thing not fully figured out yet I’m sure installing the ground will at worst case do nothing but best case really help out with the corrosion thing.  So I figure I might as well do it.

gulfarea

@Dutch061 Very good info thanks. I did a contanuity check from the battery neg termnal to the 110 female wall ground receptical ground pin (no AC power hooked up) on my 2019 320 and had good continuity reading with my Simpson meter (with Alde unplugged). Same good reading from the (unplugded) metal top of the Alde to the electrical plug ground pin on the cable from the Alde. Without tearing into the T@B wiring any further it looks like somwhere there is a ground connection between the two. I could be reading it wrong but somewhere I do have a ground crossover between the battery neg and the house ground. Again thanks for your info. Sure would be nice not to have corroded fins or tubes they are mounted on. Art

Dutch061

Okay, I just wanted to provide a couple of photos and a provide a bit more explanation as to what I done.

First, my negative lead of my voltmeter was attached directly to the negative terminal of the battery. I then used the positive lead to touch the various "points of interest" to see the voltage drop. What should that number actually be? Unfortunately, it is somewhat subjective meaning that you can find anything from 5% (14 x .05 = .7 Volts) to .5 volts on a power circuit and .3 volts on a ground circuit. All I can say for sure is the lower the number the better off you are.

I ran my additional ground wire from the Battery Junction Block Negative directly to the Alde and my PD9160ALV.

I used a 3/16" pop rivet and shake proof washer (aka star washer) to attach the wire to the Alde.



I drilled a 3/16" hole in the Alde mounting bracket and attached my auxiliary ground wire with the rivet. I installed the washer between the terminal and the Alde.



From there, my readings went to nearly zero. I think the voltage drop was .002 

I can't say this necessary for all campers, but for the easy install and additional peace of mind, I think it is worth it.

It may be of interest for those who are using the OEM installed WFCO Converter with the long run of 8-gauge wire to the Batteries to either add a redundant 8-gauge or install a 6-gauge ground wire as per the Airstream bulletin. If you were to do this for the positive wire too, this would help to address the charging issues that you have with the WFCO.

Since I am using a PD9160ALV that is within 12 inches of the Battery Junction, it is not an issue for me.

After all, the grounds were a big item in the Airstream bulletin.

Brad

qhumberd

Bravo to @Dutch061 for this investigation and explanation! While I am not a chemist or electrician, I can follow the logic and the current and voltage findings and the solution is quite easy and I might say elegant. I replaced my fluid with Century TF-1 last year and now will add the ground in my 400. I am wondering if there really is a reason to change to the more expensive Rhomar water if the root cause is as @Dutch061 has described. The Century Fluid is certainly less expensive as so far easier to source.

Denny16

Airstream made both changes, grounding and the new Rhomar fluid.  Best to error on the side of caution.  I plan to do both, increase the size of my Alde ground and changing to the new Rhomar fluid at my next Alde glycol change this summer.
 Cheers 

Dutch061

@Denny16, I think it is also important to point out if the location of your power Distribution Center (which contains your WFCO Converter) is a large distance form your batteries that it is a really good idea to put a larger gauge wire for the ground circuit between the two. I used a 14-gauge wire for my "auxiliary ground" that was added between the Alde and the Battery Junction Block. 

Example, in our 2020 400 BDL, the Power Distribution Center is under the dinette on the door side of the camper and the batteries are under the bed. If I was still using the WFCO Converter, I think it would be imperative that a larger gauge ground wire (or adding a second 8-gauge wire) between the two be installed. However, since I am using a PD9160ALV that is within 12 inches of the battery junction block and is connected with 4-gauge cable I didn't bother with that step.

Bottom line, I don't think you can have too many or too large of gauge wiring for the ground circuits. And if you were to upgrade the power wire to between the Power Distribution Center and the batteries you would potentially fix the WFCO converter not being able to use the Bulk Mode of charge.

Brad

bergger

In our 2021 the converter is located in the middle of the galley by the floor.  So a bit closer than the dinette.  But I'll use a large wire anyway.  I still do not understand electricity and grounds but this seems easy.  Connect a wire at both ends.  I see that you attached one end to the Alde mounting bracket.  Is the other end that you connected to the battery junction block near the convertor or is in in the convertor.  I guess I just to not understand where that junction block is.  Also is there a reason you used a new rivet to attach the ground instead of just attaching it to an existing screw in the Alde mounting bracket? 

Also I found an article on NuCamps site explaining how to re-ground your Alde.  It is from 2019.  I guess in the older units they had a problem with the Alde blowing fuses. That problem appears to have been corrected in later models.  So I assume the grounding in this discussion is different and in addition to the grounding discussed in the old NuCamp article? Thanks and sorry for my ignorance in this matter. 

Dutch061

@bergger, On 2020 MY, the batteries are installed behind a bulkhead with cables run out to a Junction Block in the general underbed area. I connected one end of my auxiliary ground to the negative on the Junction Block (I didn't want to have to remove the portion of the bed over the batteries again) and used a rivet to make the connection to the Alde. I used a rivet because the Alde mounting screws are installed into the floor and the floor (at least on a 2020) is Azdel and doesn't have much holding power. When I connected to the screw, the wire simply wasn't tight and if it isn't tight, it is pretty much a poor connection and of no value. Which is also why I added in a star washer.

In the photo below, you can see the batteries, but the Junction Block is hidden directly below the display for the Victron BMV-712. I finally installed the display above the Alde thermostat last month. Had a hard time convincing myself to cut a 2" hole in the cabinetry.



In the second picture below, you can see the Junction Block, you can see the cables running into the Junction (it has a black cover with writing). I put an arrow on the phot to point it out.



Hope that helps!

Brad

bergger

Thanks!  I'll just have to find that junction block. The battery placement is very similar to yours but the junction block and the 40amp fuse block are not there.  I know the 40 amp fuse block is mounted in the exterior storage compartment.  Here is a pic of my battery compartment and based on where the positive and negative battery wires disappear  I believe the junction block is mounted in the same general area.  If I remember from installing my victron shunt I'll have to remove the bed panel under the tv to access it.   I'll open it all up next week and have a look see.  

Denny16

Yes bergger, the battery junction/distribution box is behind the panel you see the battery wires disappear through.  Pull the plywood cover under the bed and you can see it.
 Cheers 

Denny16

Dutch061 said:

@Denny16, I think it is also important to point out if the location of your power Distribution Center (which contains your WFCO Converter) is a large distance form your batteries that it is a really good idea to put a larger gauge wire for the ground circuit between the two. I used a 14-gauge wire for my "auxiliary ground" that was added between the Alde and the Battery Junction Block. 

Example, in our 2020 400 BDL, the Power Distribution Center is under the dinette on the door side of the camper and the batteries are under the bed. If I was still using the WFCO Converter, I think it would be imperative that a larger gauge ground wire (or adding a second 8-gauge wire) between the two be installed. However, since I am using a PD9160ALV that is within 12 inches of the battery junction block and is connected with 4-gauge cable I didn't bother with that step.

Bottom line, I don't think you can have too many or too large of gauge wiring for the ground circuits. And if you were to upgrade the power wire to between the Power Distribution Center and the batteries you would potentially fix the WFCO converter not being able to use the Bulk Mode of charge.

Brad

Brad, I agree, the grounding wire needs to be big enough to handle the current flow between the Alde and power distribution WACO setup. I would use no 6 ground wire or run a second no 8, as you suggested.
Cheers

bergger

I just pulled up the TSB for Airstream and do see that they added the ground between the Alde and distribution block, with a 14ga wire, and then replaced the ground between the converter and distribution block with a 6ga wire.  Now my converter is in the middle of my galley, much, much closer than the converter in a 30' Airstream Classic, hence their 6ga wire.  I'm not sure what gauge wire NuCamp has used for the ground between the converter and block but do you think it is necessary to replace that based on where my converteris located?  Not sure how easy that will be to fish through.  Also I will probably use an 10 or 8ga wire from the Alde to the block.  Do you think that is overkill since it is only about 4-5 feet distance. Airstream used a 14ga and again the distance is much greater than in my 400.  

Dutch061

For the "auxiliary ground wire" for the Alde to the Batteries or Junction Block, 14-gauge is more than sufficient. After all, you are not completing an actual ground circuit, but are adding an additional ground to prevent "transient current" or even static electricity from building within the Alde system and using the heat transfer fluid as a path to ground.

Galvanic action occurs when you have dissimilar metals involved and something that will conduct electricity, in this case the heat transfer fluid or coolant. If you add a ground to dissipate that "transient current" or static electricity you remove the "electrically induced galvanic action". By keeping the heat transfer fluid PH neutral and the corrosion package fresh, you eliminate the system becoming a large battery.

IE dissimilar metals and an acidic heat transfer fluid allows a voltage to be created within the system even if it was sitting on a board without wiring connected. When this happens, you will have an anode and a cathode which will allow the transfer of electrons (and metal) from one to the other.

For the ground wire between the Power Distribution Center (PDC) and the Batteries, I can only reference what Airstream is recommending. I have no idea the distance between the batteries and PDC on their campers, but it certainly is an important part of their recommended fix or prevention.

But here are my thoughts on this, the danger of the insufficient gauge ground is likely only when the camper is on shore power and the batteries are drawn down and charging. In this situation, the WFCO Converter is attempting to use the "Bulk Charging Mode" to force as many amps back into the batteries as it can. In this situation, it would be possible for the current to "back-feed" though other grounds in an attempt to complete the circuit to the batteries. Of course, one of those grounds would be the Alde. 

As mentioned, I have removed the WFCO Converter and replaced it with a Progressive Dynamics that is mounted in close proximity to my Battery Junction Block. You can see this in the second picture that I posted earlier. So, I am not concerned about adding a second 8-gauge wire or putting in a 6-gauge wire between my PDC and Batteries. There is nothing that is 12 VDC that I operate via the PDC that will ever exceed 15 amps combined. That would only be if the refrigerator (we have the smaller refrigerator), the water pump, all lights, and the Alde are all running at the same time, which is not likely. 

Agan, I hope this helps other to better understand what is happening and why Airstream is adding the grounds. 

Brad

jimcenname

@Dutch061 Brad, Why not run the new aux ground wire from the Alde case directly to ground? By running it to the negative terminal of the battery isn't there a risk current will in-fact pass thought the Alde case? (You sound more knowledgeable than me, but I have to ask this). Jim

Dutch061

@jimcenname

Jim,

When I done the voltage drop tests on our camper, the Battery Negative Bus Bar, Camper Frame, and the 120 VAC ground were all great with less than .002 volts drop across them. Even though the frame "should be a common ground", it may not be a good ground.

With that thought in mind, when you look at the information in the Airstream bulletin, they are asking that the auxiliary ground to be installed between the Alde and the PDC and then a larger wire between the PDC and the batteries. Again, not knowing the distance between the PDC, the Alde, and the batteries I can't speak to their exact instructions.

However, if you were to install the larger wire between the PDC and the batteries and then install the auxiliary ground between the Alde and the batteries, you are essentially doing the same thing but with less effort and less disassembly (hopefully).

Although I am borderline OCD and certainly a perfectionist (aka anal-ytical) I try to be efficient even when my mind doesn't want to allow it.

Brad

jimcenname

@Dutch061 Brad, thanks. I have not yet added the aux ground yet I measured zero voltage drop between the neg term on the battery dist block and the Alde casing and zero resistance between the Alde case and ground. The measured voltage was 13.65 VDC between the two terminals of the power distribution block as well between the neg term and the Adle. Yet I have a few slightly bulging hoses (corrosion) in my system. I swapped to Rhomar water last December. I'll do the aux ground anyway.

db_cooper

Well I definitely want to add the ground wire to our 2015 320.   Does anyone know where I would need to connect the battery side wire?   Our battery is outside, and I'm assuming I would connect it upstream of the WFCO converter?  We're away from our camper for a couple months, so I can't go take a look.

Dutch061

@jimcenname, you are saying that you measured 13.65 volts between the Alde case and the negative terminal? If so, that is likely the culprit behind the bulging convectors.

@db_cooper, I would suggest getting a good look at things and doing some voltage drop testing to help guide you. But, in a general sense I would suggest adding the larger gauge wire between the PDC and the battery and then running the auxiliary ground from the Alde to the PDC as per the Airstream bulletin.

Brad

qhumberd

BTW @Dutch061 did you or someone on this thread post the Airstream bulletin that is being referenced? See below; now attached to a subsequent message.

jimcenname

@Dutch061 @db_cooper I didn't say that correctly.  I meant 13.65 vdc between the positive terminal and the Alde case, exactly the same as across the power distribution terminals, which indicates it's grounded well. 

qhumberd

Here is the bulletin that @Dutch061 posted in the other thread. Sorry I did not see it earlier. The description for flushing is quite like the @ScottG and similar procedures in our forum. I think we may be getting to the bottom of this Alde mystery at last. Science does work!