Corrosion of Alde Convectors

pthomas745 · August 2022

@ChrisFix Thanks, I'm confirming with the owner on the build date. The glycol change didn't happen until late Dec 2020. I should never get involved in counting things until I've had coffee in the morning!

Freespirit · August 2022

In our TAB 320 in the same location as the “pipe” he removed and replaced with copper tubing, it contained a check valve for the system. Not sure if the 400 is similarly configured.

BrianZ · March 2023

I've been running our Alde during these winter months, and while I hadn't intended to inspect any Alde convector pipes until later this year when we're due for a glycol change, I thought I'd at least check our glycol tank level. Imagine my surprise when I found the tank empty, and adding a quart did not give me a visible level! After checking all floor level compartments, it appeared there was no evidence of a leak. I added more & still nothing in the tank, so checked the outside drain valve. It was fine, but there was a stream of glycol dripping from both rear corners, so we had a leak somewhere, and it was not coming from under the tank.

So, after making sure the Alde was turned off, I would need to get the rear cabinet removed (oh joy!) and inspect rear hoses & convectors. Here's what I found..

And a closer view..

And by the way, here's how that same convector stub looked in 2021 when I cleaned & treated all of them..

They are nearly identical looking as far as any corrosion, so it appears the clear coating & heat-shrink tubing did the job. However, notice that the tubing came off with the hose, so the adhesive coating inside the tubing didn't do much. And it would appear that leaving just one spring clamp was not enough to prevent the hose from slipping off. Beyond that, it's not clear to me when the hose might have come off, though I was working in the Alde compartment for wintering last Nov.

In the above photo, the arrow shows the direction that I could slide the hose back & forth, with about 2 inches of play while it was disconnected. So, I wonder if that kind of stress (even from accelerating & braking) could contribute to its loosening.

In any case, I replaced the old heat-shrink tubing with a new piece..

And then I added a second screw-type hose clamp to secure the hose..

I've also ordered more clamps to doubly secure each of the other hose connections. Wish I had followed both of @rh5555 's pieces of advice on this from the start.

I guess this just shows the extent of what many of us are willing to do in order to keep that wonderful quiet warmth that only our Aldes can provide!

Live & Learn!
(And some of us still learn the hard way.)

dsfdogs · March 2023

@BrianZ I don't see the photos...I'm on my computer not a phone...anyone else see them?

BrianZ · March 2023

How about now, @dsfdogs ?

I lost them all when editing, then had to re-upload. Not sure what the issue is, but may be on my end with a new phone update.

dsfdogs · March 2023

@BrianZ Yes, I see them now! Thanks!

bergger · March 2023

I wonder if the protective tubing you've put on gets slippery when the convectors heat up? The adhesive that is on them may warm up and cause the tubing to slide off. I'd probably not use that and just treat the convector stubs and either double clamp them or use a single worm drive clamp.

BrianZ · March 2023

PS:
And here's a question..
When I poured glycol into the tank, which end of the hose would it have leaked out from?

If I had been running the Alde pump prior to & while adding glycol, then same question?

BrianZ · March 2023

Yes, I've wondered about that too, @bergger, though the description mentioned "good sealing, corrosion resistance and high temperature resistance".

https://a.co/d/blfFvWd

PS:
If I were doing this over, I would use a heatshrink tubing that does not have adhesive. But for now, I will be adding a second hose clamp of the screw type to each hose connection, and leave the original spring type clamp in place. I also plan to somehow secure the hose that came lose by bracing it somehow to prevent movement that might pull on its connection to the convector pipe. Other pipe/hose connections using the same heat shrink tubing do not appear to have any issues.

RMo · March 2023

Image: https://us.v-cdn.net/5021717/uploads/editor/wu/jrbzu6qfmind.jpg

Happiness is no bulges and connectors that look like this! I feel very lucky!

sequimite · March 2023

My expansion tank was empty and it took about a liter of old Century to get to the "min" line. So I went looking for a leak I discovered a small leak at the bulging hose on the driver's side of the rear convector. The leak was slow enough that it appears most of the fluid evaporated. Other hose connections are bulging, so I'm going to disassemble all the plumbing, clean everything, treat the stubs and refill with Rhomar. Some of the hoses look like they might be custom molded, and so perhaps proprietary. What are other's experience with replacement hoses? Will I need to order those from nuCamp?

fstop32 · March 2023

@sequimite, I was able to get my hands on an Alde parts catalog which had lots of pre-moulded options available which I took advantage of when I put my system back together. I had to do some sweet talking with the contact at Truma/Alde but they sold me everything I needed. NuCamp didn't use any formed hoses back in 2015 so I would not have been able to get any pre-moulded hoses from them. PM me if you are interested in pursuing that option.
@BrianZ, I noticed that heat shrink sticking out of the hose before I read your comment about it...I hated to see that! I used extra hose clamps to stabilize my hoses between hose to metal connections and to maintain the downward slope so I wouldn't have any pockets at drain time so I hope that also took care of any "tugging" at the hose to tubing connection points. And I double clamped all the hose to metal connections when I put mine together. Good to see the aluminum was nice and clean! I think @bergger has the right thought about heat causing the adhesive to get slippery.

BrianZ · March 2023

I think you've got the right approach, @fstop32, with the double clamps. So, yesterday I added the screw clamps to all of our convector connections plus a few others. Here's the rear convector passenger side..

Image: https://us.v-cdn.net/5021717/uploads/editor/ep/gs4joeceyldb.jpg

I had almost forgotten what a pain it is to work in this back corner using only one arm! I managed to get all the spring clamps moved & extra screw clamps added, but only after dropping multiple items that I had to retrieve, including a small flashlight that fell behind the plywood panel into the netherworld. And here's the driver's side of the rear convector, where the upper hose had come off..

Image: https://us.v-cdn.net/5021717/uploads/editor/vn/y7fjccfey9rw.jpg

I plan to add the rubber-lined steel hose clamp shown, to further secure that top hose which had come loose.

I also added clamps to my 3-way flush valve on the Alde hose between the pump & drain outlet..

Image: https://us.v-cdn.net/5021717/uploads/editor/ly/aqpio83u0eig.jpg

Hoping that this will be the end of any leaks, and with more glycol due to be delivered today, we should have the Alde working again soon - Just in time for the warm weather!

BridgerSunset · March 2023

@BrianZ @fstop32 @bergger @ScottG et al; and those who have gone before:

As I'll be tackling my first Alde inspections & Rhomar flush in a few weeks, I wanted to thank you warriors for your contributions & what to look for. Your efforts mean a lot to the community.

On a side note, what's going to be interesting to see is what, if any, damage happened this winter when we saw -50 deg F air temp in the neighborhood one night. We store the 400 outside. I think the cold at least shifted the water plumbing because pink antifreeze dribbled out from under the bathroom sink. That's likely minor. Hoping the Rhomar freeze protection rating worked in the Alde system. Still have snow to move before I can test things. More on this later.

AnOldUR · March 2023

Hey @BrianZ, you still need the Alde for hot water even in warm weather.

Nice job! I’ll be attempting the same.

BrianZ · March 2023

Thanks, @AnOldUR, yeah, I forgot about hot showers!
Also, I just realized from reviewing some of my previous documentation of my 3-way valve (show in my last photo above) that I had used regular heat shrink tubing on my valve connections, not the kind with glue, so at least those will be more secure.
Today, I also added a hose clamp to the top rear convector hose on the driver side to prevent any movement of the hose from pulling it off..

I got this clamp from the electrical supply area at our local Lowes hardware..

I had to put it some distance from the convector where it could be mounted flat against the backing surface.

BrianZ · March 2023

Wow, @BridgerSunset, minus 50°F and still have snow on the ground! And here in central VA we've got trees & flowers blooming already. I don't know about Rhomar, but that temp is close to our old yellow glycol's minus 48°F cloud point where it gets slushy, but not solid until minus 100.
Sink drain leaks can be fairly common & parts easy to get, at least with slip joints.
Let us know how your exchange goes.

bergger · March 2023

Flowers blooming! We've still got 3 feet of snow on the ground and it's snowing right now! Hoping to de-winterize by early May! I'm itching to get the trailer uncovered!!!

ChanW · March 2023

Well, I gotta say @bergger, living in a place with the name "Leadville", you had to expect it, right? There's no way that name doesn't sound cold! Brrrr!
Buffalo was still 18° yesterday morning and we got about 2 in. overnight. But it melted away with an amazing sunny day. (Thank the gods! I think I can count the number of sunny days here this winter on my fingers.)
Happy spring! It will come!

bergger · April 2023

It may be cold and snowy here for long stretches but we are blessed with way more sunny days than cloudy days! Even in the winter! Sunny and 39 degrees today, a heat wave!

DanWeitzel · April 2023

Just completed my Alde repairs. Used the shop vac method of fluid removal, got 2 gallons out and didn't find any more when opening up the system. Removed all 4 convectors and found some budging/corrosion on several. Interestingly the corrosion was on the inlet side of the convectors. Also found white powdery stuff on the convector stubs so NuCamp must have used the Locktite MR5923 during assembly (2016 model YR). I purchased new convectors & misc. fittings in case I needed them but decided to clean & reuse the existing hardware, saving the new stuff for the future. Several of the convector stubs were in bad shape, with slight perforations to the inside. Cut off the bad areas and removed several of the fins to compensate. Cleaned the stubs real good and installed heat shrink tubing as some others have done. Reinstalled convectors and double clamped, using one stock clamp and one worm gear clamp. I also replaced all the straight thru connector, these were also corroded, with new factory plastic ones . Since these straight thru connectors are plastic I only single clamped them with the stock clamps. Refilled the system with new transfer fluid and ran the pump for a couple of hours to remove any air. Next heated up the Alde and checked for leaks, thankfully none.

sequimite · April 2023

I've exhausted all reasonable sources of OEM Alde convector hose for my Alde 3010. Even Alde dealers are not sure they can order it for resale because, for many parts, Alde insists an authorized dealer install the part and prohibits parts sales to the end customer. Also, some dealers listed say they are a Truma dealer, but not an Alde dealer. They can see the part in their system, but can't order it.

I bought a short length of 7/8 in ID heater hose to replace the short hose between the reservoir and the rear convector that has cracked open at the bulge and is leaking. I have not installed it yet, but I'm concerned that since 7/8 in is slightly larger than 22 mm that I won't get a good seal, even with a clamp.

If my hoses are damaged beyond repair (beyond the short one mentioned above), I'm leaning toward replacing the damaged hoses with PEX-A. The convector stubs are 22 mm and the Alde convector hose ID is 21.4 mm--I assume to create a snug fit. I can choose PEX ID of 19.05 mm which would need to be expanded and would then contract around the stub. Or PEX with an ID of 21.895 mm which should slip on without expansion. Either way, I intend to install a clamp. Any thoughts on which size would be more leak-proof and/or durable long-term? Will PEX-A be compatible with the Rhomar glycol and associated corrosion inhibitors?

@fstop32and others that had major corrosion--did you replace your convector hoses or use the damaged, bulging ones? I hate to put those back as I think it will reduce the effectiveness of the clamp. Also, there does not seem to be any slack in the hoses that would allow me to cut off the damaged end.

I had expressed to a helpful dealer that Alde/Truma does not make it easy for an owner to repair their own rig. She had the interesting comment that she agreed with my thought about Alde, but she finds it to be true of the RV industry in general, unlike the auto industry from which she came.

DanWeitzel · April 2023

Try this site, I think you can buy directly from them. https://www.alde.us/our-products/?categories=heating-systems,assembly-parts-rubber,22-mm

sequimite · April 2023

DanWeitzel said:

Try this site, I think you can buy directly from them. https://www.alde.us/our-products/?categories=heating-systems,assembly-parts-rubber,22-mm

Sadly, that page is for reference only. I see no way to buy an item and I was told directly by Alde/Truma that they don't sell to the general public. One must buy from a dealer. Some listed dealers deny Alde dealer status and others are simply not helpful. This has been a nightmarish quest for parts.

Two dealers called back this afternoon. One said Truma wants the S/N of my 3010 and a photo of the part. It's bulk hose sold by the foot. They know what it is. The other was told that the 3010 is obsolete and very few parts are available at this point. My T@B is less than 7 years old. Parts should be available. Imagine if you could not get a radiator hose for a 2016 Ford because it is considered obsolete!

DanWeitzel · April 2023

I purchased my spares from a guy here on the forum by the name of Freespirit. He was able to buy Alde parts from some source. Try connecting him to see if he can help.

Dalehelman · April 2023

@seq
This tape permanently self bonding to it self. A couple of wraps around the convector end would make up the difference between 7/8 hose and the 22mm convector end. Not to mention it’s handy to have around.

Rescue Tape Self-fusing Silicone Tape (Clamshell White, 1-Inch by 12-Feet) https://a.co/d/fioUm2Y
sorry the link doesn’t seem to work.
just search Amazon

Sharon_is_SAM · April 2023

@Dalehelman and @sequimite - the link to Amazon works. Instead of tapping the link, press and hold it on your device and you can open it in another page.

fstop32 · April 2023

@sequimite , as mentioned previously I totally replaced all my tubing and was able to purchase directly from Truma/Alde at their Elkhart location. That was 2.5 years ago and they could have changed their policies since then. Back then the general principle was they would sell parts only if you walked into their facility but they were not in the parts shipping business. I was fortunate to find someone there who was willing to help me out.

I would think the 7/8" heater hose would work fine. If you need to make it a bit more snug you can use @Dalehelman suggestion or the 1" heat shrink tubing idea that @BrianZ and I have done...but double clamp connections.
While I did replace all my hose I did cut the bulged ends off the old hoses and kept the rest for "rescue operations" in the future. If you end up only needing a shorter piece of hose contact me and I can probably help you out.

I have no idea if PEX would stand up to glycol but even if it does I would think it would be difficult to work with in the tight confines of a T@b, plus the reflex memory of PEX would be applying stress at most every joint connection.
I think I would go with the 7/8" hose over PEX.

Dalehelman · April 2023

@sha
Thanks learn something new everyday.

BrianZ · April 2023

For what it's worth, here is the parts ordering info I found here in the forum, though I don't know if it's still current, or applicable to Alde parts..
https://tab-rv.vanillacommunity.com/discussion/14285/retail-parts-order-form#latest
And also this page with the pdf order form for sending to a dealer as well as a link for finding a dealer based on zip code..
https://nucamprv.freshdesk.com/support/solutions/articles/44002257552-part-ordering
They do indicate "The form simply asks for your VIN, a picture of the part, and an address for shipping, be it to your dealer or direct to your address".
I seem to recall that NuCamp's process was that orders for parts would be paid to a dealer, who would then submit to NuCamp, who would drop-ship directly to you. However, it's not clear to me whether that process is the same for Alde parts, which are not unique to NuCamp, since Airstream uses Alde too.

Also, there is an extensive list with photos of various Alde parts at the Truma site..
https://www.alde.us/our-products/
Although, they do acknowledge there is no means of ordering direct online from them.

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