Changing out the Alde fluid.

tombeaux · September 2023

@Horigan - You are correct. I should not have used the word "dry," because there is a small amount of residue, but certainly dry enough for a fluid change and to avoid making a mess while dealing with the corrosion.

bergger · September 2023

I use both the shop vac and a small 12v pump at the same time. Both are used in the reservoir tank. I also have the Alde circulation pump on. The alde pump circulates the fluid, The shop vac sucks it out on its return to the reservoir via the return tube of the reservoir and the 12v pump pumps new fluid into the system via the outflow tube in the reservoir. All working at the same time. It does require two people as sometimes the old fluid gets sucked out faster than new fluid enters or vice versa. I simply tell my wife to turn on or off the vac or the pump as I hold the tubes into their respective places in the reservoir.

Barbb · October 2023

I have a 2021 Tab 320s boondocker. Can I use Truma Alde Glycol from Amazon or do I have to get rhomar glycol?

manyman297 · October 2023

@Barbb They’re identical. I think Alde adds a dye to theirs but they basically get it from Rhomar and rebrand it.

pthomas745 · October 2023

@barbb, please tell us your "build date". Send us the link to the products you are considering.

Trailers before Dec 2020 (which might be called 2021's) came equipped with Century brand of glycol.

Trailers after Dec 2020 came equipped with "Rhomar" named glycol, which Alde, in typical confuse the consumer fashion, seems to re-bottle and call "Alde Glycol!"

So, look on the driver's side tongue of your trailer for the gray sticker. In the upper right corner, there should be a month and a year. That is your build date. Compare that build date to this information release from NuCamp.

https://nucamprv.freshdesk.com/support/solutions/articles/44002156353-2021-glycol-change

manyman297 · October 2023

Century (the old glycol) is yellow in color. The new Rhomar glycol is tinted bluish green. Just take a peek at your reservoir.

Barbb · October 2023

Thanks for the comments.my manufacture date is 4/21. I bought the Alde glycol - bluish one.

pthomas745 · October 2023

I've been gathering the pump/tubes, etc, for a real glycol change on my 2017. I knew the expansion tank location was a bit cramped, but as soon as I looked really closely at what I needed to get into the tank, and how I needed to see into the tank, I realized that making the "pump" idea work would be needlessly difficult.

On page 15 of this thread, @ScottG pointed out that the simplest method of getting the old glycol out is by disconnecting the hose from the side of the Air Bleeder Valve that leads down to the first convector. With the hose open, just introduce enough air into the system and "blow" the glycol out: it will eventually make its way to the expansion tank, and then straight out through the glycol drain.

https://tab-rv.vanillacommunity.com/discussion/comment/165276/#Comment_165276

(I'm still looking for the original comments on this...I suspect they may be in the Dale Helman thread about using a shop vac to draw the glycol out of the system.)

Has anyone tried this?

I really need to get to the convector behind the storage areas in the back of the trailer for an inspection. Which means the whole back wood work area at the end of the bed has to come out. @BrianZ has a comment in the "Corrosion" thread that explains how and has a picture, but it isn't clear to me if the design of his trailer (a 2018) is the same as my 2017. Here is Brian's comment with a photo of the back "shelf" removed:

https://tab-rv.vanillacommunity.com/discussion/comment/167199/#Comment_167199

This is what my back shelf area looks like. The shelves seem to be the same, but the differences seem to be the sections of wall running up to the outlets/charging center on each side. After unscrewing the little wood puzzle on the left of the picture (the slide out covering the expansion tank area is already removed on the right side) I would have to disconnect the wiring for the charging center. Maybe disconnect the electrical outlet. Anyone performed this version of Tab Yoga on a 2017?

Image: https://us.v-cdn.net/5021717/uploads/editor/l5/3yptzisxntpg.jpg

DanWeitzel · October 2023

Our 2016 is a little different with the back shelf going completely across the whole trailer. There is a lift out panel (remove a couple of screws) and I can access the entire back area. I did use the shop vac method with good results, but have straight in access to the over-flow tank. You could try making an adaptor out of PVC pipe, 90 degrees to allow the shop vac to suck from the tank. Here is a pic of my back wall.

AnOldUR · October 2023

@pthomas745, this is not a mod that you or anyone else might want to risk or undertake. When I did my bed mod I had to move the expansion tank. It's now located under the bed in the Alde compartment. At this location my glycol exchange or even just checking the level is much better. It wasn't easy, but in the long run very worth it.

Most sources stuck to the party line of, "mount the expansion tank at least 7.5 inches (200 mm) higher than the highest point of the heating system or boiler", but my engineer son said that as long as there was no cavitation there shouldn't be a problem. We've been using it this way for three seasons (around 30K mile of travel) with no problems.

Image: https://us.v-cdn.net/5021717/uploads/editor/4i/6ffgeaz5mhxh.jpg

AnOldUR · October 2023

DanWeitzel said:

Our 2016 is a little different with the back shelf going completely across the whole trailer.

Since it's above the shelf in the newer modes, I'm curious at to where the expansion tank is located in the 2016?

DanWeitzel · October 2023

In our 2016 QMax model the expansion tank in located on the driver's side rear under the back shelf. See circled area in the pic.

ScottG · October 2023

pthomas745 said:

...
On page 15 of this thread, @ScottG pointed out that the simplest method of getting the old glycol out is by disconnecting the hose from the side of the Air Bleeder Valve that leads down to the first convector. With the hose open, just introduce enough air into the system and "blow" the glycol out: it will eventually make its way to the expansion tank, and then straight out through the glycol drain.
https://tab-rv.vanillacommunity.com/discussion/comment/165276/#Comment_165276
(I'm still looking for the original comments on this...I suspect they may be in the Dale Helman thread about using a shop vac to draw the glycol out of the system.)
Has anyone tried this?
...

Hmmm. I just went back to that comment and realized the reference/link I had provided (and have now removed) looped right back to the exact same discussion.

I no longer remember what it was supposed to be referencing, but I don't recall any earlier or additional comments on the topic. This was something I came up with on the fly while changing my glycol, and incorporated it into Appendix A of the DIY Alde Glycol Exchange manual. I don't know if anyone else has used this approach, but it worked surprisingly well for me.

pthomas745 · October 2023

Thanks, Scott. I'm going to wander back through Mr Helman's shop vac thread and see if I can find a reference there. Leave it to me to find that "one weird trick". I must say, after sifting over this thread repeatedly, I'm a little surprised how simple the glycol plumbing turned out.

tombeaux · October 2023

@pthomas745 - Our 320S is a late 2017. That shelf unit is identical to a 2018 and we have had it out a couple of times (once to retrieve an iPhone and the other to clean the fittings on the Alde system). It helps to have a second set of hands getting it out, but I never had to roll on my back to get it out. It does help to have a right angle driver with the square bit as a screwdriver will be too long for the screws on the long edge.

pthomas745 · October 2023

@tombeaux Thank you. How was the electrical outlet on the passenger side dealt with? Take the cover off and leave the outlet connected? The power center on the other side just has simple press on connectors.

Haneydp · November 2023

I have a 2017 T@B 320 clamshell. I recently took it to my closest NuCamp dealer for brakes, a wheel bearing repack, and to exchange 4-year-old Alde fluid. To my surprise they told me that NuCamp now recommends NOT changing the Alde fluid--that it doesn't go bad and that the danger of introducing air pockets outweighs the advantage of changing the fluid. Has anyone else heard this?

ScottG · November 2023

@Haneydp, I have not previously heard this recommendation, and if it were true (which I doubt) it would certainly represent a suspicious about-face on the part of nuCamp and Truma-Alde.

That said, I've always thought the two year change interval was probably a bit conservative. In the past, owners have tested the pH and specific gravity of old and new glycol, and found little evidence of changes with age and use. However, reliable guidance or hard data on the loss of the glycol's anti-corrosive properties has been difficult to acquire.

And while air pockets may pose a bit of a challenge to burp out after a glycol replacement, I'm skeptical that they pose a "danger" of any sort.

AnOldUR · November 2023

@Haneydp you should ask nuCamp this question and also let them know who this dealer is.

customerservice@nucamprv.com

pthomas745 · November 2023

@Haneydp this is another in an endless stream of bad information from every direction about the Alde and the glycol. This thread is 7 years long, and there are another couple of threads about the Alde glycol. And, threads about the corrosion of the Alde convectors. The only way you can inoculate yourself from "weird things dealer say" is to run through this thread from the beginning. You will learn more than you can imagine about the Alde and the glycol. The comment from your dealer is just wrong.

manyman297 · November 2023

As much as I want to believe what that dealer said, my guess is they’re misinformed. I would love to go 4 years without having to do the exchange.

Sharon_is_SAM · November 2023

@Haneydp - try help@nucamprv.com

ReenieG · December 2023

ScottG said:

Okay, as much as I prefer talking about work as opposed to actually doing it, after sixteen months of planning and discussion it was finally time to tackle replacing the original glycol in my 2015.

The entire project ended up being more involved than planned because I wanted to inspect and mitigate potential corrosion in the convector loops in advance of the actual fluid change. I won't get into the details of that here, but if you are interested you can read about in this discussion.

My approach to this was not much different than that described by @gregndeb several pages back, so I won't rehash minutiae that has already been well detailed. The primary difference in my approach was the use of a simple hand-operated transfer pump. With a few minor wrinkles, I'll say this turned out to be stupidly easy...

The Equipment:

Two "gregndeb" adapters made from solid toilet risers and #2 drilled stoppers, three lengths of 3/8" ID x 1/2" OD tubing, two hose clamps, and an inexpensive transfer pump. (I chose this pump because it was clear and could be easily disassembled for cleaning.) The large bin was used to keep everything contained and mitigate spills. Total cost < $30.

Draining:

I think this step is entirely optional, particularly if the old glycol looks good and you have kept up with regular changes. Read on if interested, or just skip ahead to Filling.
Pull the drain plug under the T@B. Enter wrinkle #1. Contrary to past reports, only the contents of the reservoir tank (about a pint or two) drained before the flow stopped.
Guessing there might be some sort of vacuum preventing the boiler itself from draining, I pulled the outlet hose from the top of the unit. (Use spill protection!) Things started flowing again and I got a full gallon drained.
As you know by now, the low point drain does not drain the glycol trapped in the convector loop. I recalled someone here talking about blowing into the system, and since the outlet hose was already disconnected, thought I'd give it a try...
I removed the section of hose containing the automatic air bleeder (which may or may not have been necessary), cleaned up the open end of the hose, and gave several good puffs. (Alternatively, I could have used the hand pump for this, as it also pumps air.) This forced the majority of the remaining glycol up into the reservoir, where it subsequently drained out through the low-point drain. I got another 2-1/2 quarts out this way. There may have been a bit of residual glycol left in the system, but not enough to lose sleep over.
Reinstall the drain plug.
Filling:

This was the easiest part...
Put the adapters into the reservoir tank and seat them firmly into their respective openings. The offset adapter connects to the pump outlet. The hose from the straight adapter runs into a drain bucket. The pump's inlet hose runs into your jug of fresh glycol. (See photos below.)
Start pumping. Enter wrinkle #2. My pump pumps mostly air. Seems it it works much better if I turn it upside down. Keep pumping. (My adapters stayed in place without my needing to hold them, so I could devote both hands to the pump.)
If the system has been drained, nothing will drain from the outlet until you have replaced almost two gallons of fluid. Once glycol started flowing into the drain bucket, I kept pumping until I collected another quart or two.
If the system has not been drained, old glycol will be forced out ahead of the new glycol being pumped in. Pump until you have collected at least two gallons in your drain bucket. The hand pump is more than up to the task of moving the fluid through the system.
Remove the adapters, top up the reservoir, and replace the cap. Set the circulator pump speed as high as it will go, and turn it on (how you do this will depend on your particular pump and control panel). On high, the pump really moves the fluid and there should be quite a ruckus in the reservoir. Within a few seconds, a pretty large bubble burped out of the reservoir and the fluid level dropped. I stopped the pump and refilled. This happened one more time, and then the level remained steady.
Continue running the pump on high for several minutes. Once you are satisfied nor more air is escaping from the reservoir, you can turn on the heat. It will take a while for the glycol to warm up, but once it does, make sure heat is reaching all the convectors. If not, you may need to take additional steps to bleed the system. I didn't.
Turn off the system, return the pump its normal operating speed, adjust the level in the reservoir, and call it a day!
Here's a couple pics of the system in action. My system was drained so fresh glycol is not yet flowing to the drain bucket.

@ScottG, I'm trying to comprehend how to build this pump. I think I may have some other problems with corrosion as well, and a possible leak, but I'm still trying to figure that out. Is it possible to have a parts list with maybe some links to the items for your pump? Or, better yet, "someone" to build me a pump and mail it to me? I think I may be reaching here, but it's worth asking.

ScottG · December 2023

@ReenieG, have you seen this DIY Alde Glycol Exchange document? It contains more details about the parts and process for constructing the pump.

Also, if you have the patience to read through the entirety of this discussion, you will see that owners have come up with several other equally effective approaches to getting the glycol exchange job done. If you elect not to go the pump route, you may find an alternative you are more comfortable with.

manyman297 · December 2023

@ReenieG ScottG's advice is spot on. Read through this thread and you'll see multiple ways you can build this pump. Mine is including here somewhere (I posted in June or July about how my process went and I'm pretty sure I included pics and a parts list).

The HARDEST part is building the pump...and building it isn't the hard part. It's finding the right fittings. And even then, looking back, it wasn't that hard. It just felt hard because it was the first time doing it. Once I did the fluid exchange there was this moment of me thinking "That's it?" I fretted over this for months and the entire process took maybe an hour and a half (that includes bleeding the bleeder valves throughout the trailer). A full-on flush will take longer but the effort isn't much more.

Once you do it you'll laugh at yourself for how easy the process actually is and then feel REALLY good about how much money and time you saved not having to haul the camper to a dealer who probably won't do it correctly anyway.

ReenieG · December 2023

To be honest, I've read through this whole thread a few years ago. I did a gravity drain only. Then, I had my fluid exchanged last year, so... here I am again and I think I can do a full exchange myself, unless of course there are parts that need repair.

manyman297 · December 2023

My experience of the exchange is on page 28 of this thread somewhere in the mid-bottom of the page. You can see I used off-the-shelf pieces of irrigation funny pipe elbows, worm clamps and vinyl tubing. The only thing I ordered was the 12v pump from amazon. The pump, to me, made all the difference and is worth the $15 or whatever I paid for the speed.

pthomas745 · December 2023

@ReenieG I have a 2017 with the same setup on the expansion tank, which makes it practically impossible to use the basic pump setup included in the "DIY Glycol Exchange" that has been developed in this thread. Even if the pump setup was modified for more flexible hoses into the tank, it would still be difficult to see that the hoses were properly placed, etc. Even with the entire back cabinets removed, it still would not be an easy task.

But.....

There is one small section of this long thread which shows a much easier way to do the exchange. On page 15, Scott G points out that disconnecting the hose that comes off the Auto Air Bleed Valve essentially gives you control over the entire glycol loop (or at least most of it) and you can push the glycol out from that point, and refill from that point also. On page 19, owner @BrianZ accesses the glycol loop in about the same spot with a more elaborate exchange setup.

https://tab-rv.vanillacommunity.com/discussion/comment/165276/#Comment_165276

Several owners near page 15 successfully used that place on the Alde to do the exchange, and reported no issues. I plan on trying this method in the next few weeks.

BrianZ · December 2023

@pthomas745, here is my Alde glycol drain/refill setup with the 3-way valve that is still working nicely..
https://tab-rv.vanillacommunity.com/discussion/comment/167657/#Comment_167657

Mobean · December 2023

So many ways to accomplish the exchange and all work well. I have to say though, ScottG document above was well written and lists inexpensive supplies. The job may seem intimidating but reading over the instructions and allowing yourself plenty of time to go slow removes a lot of the stress. The only addition I made was to use a #10 rubber stopper https://www.widgetco.com/products/10-rubber-stoppers?_pos=2&_sid=7e1412c0b&_ss=r and a hollow punch set https://www.harborfreight.com/6-piece-hollow-punch-set-67030.html to fashion a way to hold the ⅜" risers in the expansion tank without a helper.

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