Fresh water pushing out glycol from the Alde

fineline72

2016 Tab CS-S
We have owned this camper for over a year now and everything has been great. We recently changed the rear faucet and now when we turn on the water pump or the city water, the glycol is pushed out of the Alde system. So far in trying to figure out the problem, we have lost over a gallon of glycol from the system.

Please let me know what I can check.

THANK YOU!!

ScottG

Peculiar. Where is the glycol that is being "pushed out" coming out?

fineline72

Front drivers side. black tube poking through the floor

ScottG

The Alde glycol plumbing is completely separate from the domestic hot and cold water plumbing. Unless you did something very, um, creative, there is no way changing out a faucet would cause this to happen.

I can think of only one way that what you describe could occur, and it's not pretty...  If the Alde core was corroded a hole could form between the glycol chamber and the internal HW tank. As you ran water under pressure through the Alde HW tank, it could seep into the glycol chamber. This would overfill the Alde's glycol plumbing, which would ultimately overflow at the expansion tank (which IIRC is behind the toilet in a 2016 CS-S) causing a leak of glycol under the trailer at that location.

I'm guessing here, but given my understanding of T@B plumbing, I don't see any other plausible explanations to what you describe. Again, this would have nothing to do with changing the faucet. If what I'm thinking is correct, it would be just a very peculiar coincidence.

fineline72

That is what i was afraid of. Thank you for the info. Are the parts availible to repair this or does the whole unit need changed?

ScottG

First, check your Alde expansion tank. If it is overfilled or overflowing, that would support my guess.

If it is the boiler core at fault, I do not think you can buy a DIY replacement part. You will need to consult with Truma/Alde for options.

MuttonChops

A possible Test of @ScottG theory might be to place the Alde Hot water side into Winter Mode.

That is turn the various levers so all water bypasses the Alde.  If the glycol no longer overflows/drains then the Adle tank may indeed be damaged - - - not a foul proof test but would be a helpful data point.

If you don't know how to set the valves (levers) this image might help
((better descriptions can be found on this forum))

fineline72

I found the problem. There was a pinhole in the weld. Time to get the TIG welder out to see if I can save it. Thank you everyone for your input and advice. .

Tabaz

Note the description of "D" above "See manual should be drained after each trip or every 10 days."  Leaving the tank full between trips with hard water conditions may cause corrosion.  As an added precaution, some of us a use a portable water softener between the water source and trailer while camping.

ScottG

@fineline32, what exactly is that a photo of? Is that the inside of the Alde?

fineline72

Yes, inside the alde. At the weld just below where the heating elements and burner mounts

N7SHG_Ham

I know of one other case where a weld failed in same location I think). The entire Alde was replaced, however that might of been a warranty replacement on a new unit. That is likely a bad weld from get go that just now showed up. I would see if you can get traction on a warranty claim, but at seven years old that might be a reach.

ScottG

fineline72 said:

Yes, inside the alde. At the weld just below where the heating elements and burner mounts

Nice. Did you take that with a scope or did you dismantle the Alde?

Per my speculation above, is the leak between the glycol chamber and the internal HW tank? Was the glycol overflowing at the expansion tank?

Sorry for all the questions, but I think you are in previously uncharted waters here so I'm very curious about the details and how you eventually resolve this. Sorry you had to be the pioneer, though...  :-/ 

BrianZ

@fineline72, Would that be located somewhere in this view? ..

fineline72

you would not be able to see it in this picture, it is under the metal and foam, but roughly where the arrow is pointing

fineline72

Once the covers are off, you can see the weld joint that was causing the problem. the outside looked perfect.

fineline72

When i first opened it up, it looked like the brown area at the weld was the problem area, but once i cleaned it, i found out it was just rust/dirt. the real problem was about 90 degrees away.

fineline72

This is where the real culprit was. Note the vertical weld for orientation. To verify it was the problem, I filled the inner tank (where the glycol would normally be) with water and pressurized the outer tank with 5psi of air and the bubbles were pretty obvious. I cleaned and dried everything and prepared to weld it. When I pre-heated it with a torch, there were embers inside the pit of the weld which told me that there was debris inside the original weld. I TIG welded it, pressure tested it overnight and reassembled. It has been working good ever since!

Thank you to everyone that gave input to help solve our problem!

BrianZ

Awesome job, and thank you for sharing the fantastic photos, @fineline72 !  The first 2 of your last 3 photos really show clearly how all the compartments of the Alde fit together, confirming what @ScottG & others have described previously.  Alde's drawings just don't show so clearly like your photos exactly how it all works. 
So, as I understand what you've shown, the location of the corroded glycol tank wall was the weld between the double tank in an area near where the longer glycol pipe enters the tank.  That would be the glycol exit pipe near the top of the unit, if I'm  not mistaken?  If so, I would surmise that this location would be more prone to corrosion, since that's where air in the glycol system would tend to collect at a high point, and the oxygen present would then contribute to the oxidation process.
What an amazing job you did tackling such a huge project.  Congrats!

PS:  The heating elements appear to be in great shape.  Also, it looks like there were a couple of other spots in that last photo with some possible corrosion, with some of the white deposits like we've  seen in our convectors.

BridgerSunset

This is another person we are very fortunate to have on this forum!
Thank you @fineline72 for your effort & aptitude, and for explaining things to us in detail.

Your efforts, like many here, really do help us all understand things a little better every day.

pthomas745

Well, this is the first picture of the Alde tank and associated heating elements I have ever seen.  I'm trying to tilt my head around to see how everything fits.  Amazing stuff, thanks!

Sharon_is_SAM

@fineline72 - it would be worthwhile to communicate with Alde/Truma regarding your handiwork.  It may help identify a quality control issue and help a future Tabber!

fstop32

Amazing stuff @fineline72, thank you for sharing the deep dive into your problem!  As others have commented it's really interesting to see behind the curtain.  I was wondering if you needed new gaskets/seals when you went to put it all back together or were the existing ones in good enough condition to not require replacement?

N7SHG_Ham

The one I saw disassembled with a weld leak was the same weld IIRC. That unit was under warranty and the entire Alde was replaced. Shop kept the old one for parts. Hopefully not too many leak there as an owner without equipment and experience to repair this will be in for an expensive repair, most shops will probably just replace.

webers3

@fineline72 I took apart my failed Alde boiler, my failed at exactly the same spot on 2017 320s. This appears to be a recurring issue. Did you report this to Alde? It was an expensive replacement 

DM159

OUTSTANDING investigative work.  The ALDE in our 2022 TAB400 drained all its glycol onto the ground in 2023 after we made it home from 6 weeks on the road.  Our dealer neglected to inform us about the ALDE Warranty Registration and we had to cover the entire replacement cost.  Thankfully Nucamp covered the new ALDE install.  I guessed that the inner tank weld failed in some fashion.  Wish I could have had time to disassemble the system looking for the failure point.  Again, outstanding work.  Thank you.      

manyman297

@DM159 that’s pretty disconcerting to have that fail so quickly. It seems like others are at least getting a couple of years before this issue arises.

Etheridges

Well, it sounds like I am next in line. Went into the shop today and saw a big puddle of antifreeze on the floor, driver side, behind the wheel. It appears to be coming from the black drain tube. I have no glycol fluid anywhere on the interior of the trailer. I feel an ALDE replacement/alternative coming on!

pthomas745

Show us a photo of where the "antifreeze" was coming from.  There are several ordinary drain tubes that the Alde's glycol could come from that may have nothing to do with the Alde hot water tank.

The "spout" under the trailer is directly below the drain tube in the Alde compartment.  Look for the Alde drain tube, which should have a solid plug attached with a hose clamp.  The other place glycol could drip would be from the black round "plug" in the trailer floor, which has several tubes in it. 

So, identify exactly what is coming from the trailer, and exactly what drain spout it is coming from. 

The Alde has its own drain pan underneath, so I believe if the tank was leaking water, you would have water in the main Alde compartment. Look over this thread that has a picture of the various drains under the trailer that explain each one for your 2017.

https://tab-rv.vanillacommunity.com/discussion/10042/alde-drain

webers3

@Etheridges To check if the water is pushing out glycol  check the glycol reservoir. If the reservoir is filling when the water pump is on then there is a breach between the water and the glycol chamber in the Alde.

mona

@Etheridges If the glycol reservoir is empty, the flow assembly (brass cap looking thing) may have stuck causing a glycol dump. It’s not unheard of. Happened to me. 

Jeannie