Corrosion of Alde Convectors

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

@BrianZ Yes, I see them now! Thanks!

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

@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 @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.

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.

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 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!

@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 

@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.