Changing out the Alde fluid.

fstop32 · February 11

@Maple_Geek my experience was I had lots of corrosion but my glycol pH still checked within acceptable range. I suspect that if we could check the pH of the glycol that seeps under the hose/convector connection probably does NOT have the same pH reading as what is flowing through the hoses or in the reservoir tank. I would not suggest only going on pH reading. Hopefully things will be different with the Rhomar but as @AnOldUR suggested we don't really have much historical data on the Rhomar yet.

pthomas745 · February 11

And, in @Maple_Geek and the dealer's defense, many of us had no idea about this issue for several years. I never gave it a thought in my 2017 until it started to become an issue in the Forums, etc. It wasn't until two years ago I even knew what to look for. ( I did one drain and replace, and that probably just emptied a gallon). So, when did my corrosion start? Right away? Immediately after 2 years? Who knows?

When I get my trailer back together, and refill with the Century, how long will the conformal coated, heat shrinked (heat shrunked?) convector ends survive, or will they survive, without a glycol change?

The only things we have really learned here are: ensure the hoses are properly connected and clamped. Look for the telltale bulges.

Maple_Geek · February 12

Thanks @pthomas745, @AnOldUR and @fstop32 for the feedback. The biggest issue I have with this liquid change is being able to find Rhomar in my area. I did check for bulging and corrosion in the fall and didn't see any evidence of it. I'll keep looking...

KatieP · April 4

Looking for advice: I am considering simply decommissioning the Alde system altogether on my 2018 T@b 2018, which I bought in 2023. We've enjoyed the camper and are looking forward to a new season. However, the previous owner didn't tell me about how she maintained the Alde, but it seems its time to change the fluid. The problem is the quote for doing it by the local dealer: It's a heart-stopper.

Has anyone just gone without heat and hot water, draining the Alde of all fluid and water, and letting it sit empty and unused? I'm guessing there would be no corrosion if it's empty. Or am I inviting more trouble?

I would still use the fresh water tank and plumbing system separate from the Alde. We don't camp in the winter and I'm fine with washing my dishes with hot water from the tea kettle.

The local dealer quoted $620 for four hours labor to flush the system and replace the fluid, with $120 for four gallons of glycol fluid. In addition, they want a hefty fee for dewinterizing the plumbing, sanitizing the water system, checking the propane lines, cleaning the air conditioner, and so . A total of nearly $1500 for all this work. I'm fairly handy, have done winterizing/dewinterizing and maintenance on previous camper trailers, but I'm not up to changing the Alde fluid myself.

What do you think? Hope to hear from someone about this issue. And thanks so much for everyone's info--I so appreciate it because it helped me generate some useful questions and pointed me to even more ideas.

Denny16 · April 4

We have a 2018 TaB 400 and have only changed the glycol fluid per nüCamp’s recommendation, and have never had an issue with the Alde system. It is a great heat source on a cold morning, here on t(e Pacifc North Coast. You can use the hot water without circulating the fluid to heat the trailer. You can also just leave it off and not use it.

I would get the fluid changed, sounds like the. 4-hr charge is to change out the old Century fluid, which requires several flushing with water, and the new Rhomar fluid. This would be a one time high maintenance charge. Future changes would only require draining the fluid and adding new fluid every two or years (nüCamp/Alde recommends every two years. The cost for this service is normally the cost of the fluid plus about one hour labor.

Or you could just change out the fluid with some new Century Fluid, and either occasionally use it, or then lay up the system and not use it. I would not leave it drained of fluid, this would allow more oxygen into the system and could cause future issues.

We just use the hot water part of the Alde, leaving the heat turned off on the control panel, and once a month run the pump,circulation feature on the control panel maintenance menu, or just run the heat for an hour to circulate the fluid, to help maintain fresh fluid in the system.

You could also just not use it, but I would not completely drain the system of glycol, or leave the old fluid in it. You can drain the hot water tank and bypass it if you do not want to heat water. You can still use the Alde for occasional heat with the water tank drained.

Sounds like you would be comfortable taking care of de-winterizing the water system, which is easy on the 2018 tab with its low point drain system. The unofficial Tab400 manual covers this process for the 2018/2019 TaB400, and is available for download on this forum. Or to have the trailer’s gas and brake systems checked, we used a local general trailer service shop, not an RV dealer, as the labor is normally less.

Cheers

Sharon_is_SAM · April 5

@KatieP - the Alde is a highlight of the nuCamp line. I understand the cost issue, but, down the road, you will be able to sell your TaB a lot easier if you maintain the system. Leaving the Alde empty of glycol will result in corrosion and if you ruin the Alde it is a cost of $2000-$3,000 to replace the system.

Try another dealer. Some Airstream dealers will do the Alde work. Another less ideal idea is to just drain it and refill with the same glycol. You can do that annually and that will at least give you fresh glycol with fresh corrosion protection.

DanWeitzel · April 5

We have a 2016 T@B QMax model (no bath), that said I changed my Alde fluid myself and it only takes 2 gals. Here are some things to check: how many convectors does your trailer have? There will be two at the back of the trailer. Two more under the passinger side bench, and possibly two more under the driver side bench. Ours only has the two in the back & two under the passinger bench. You want to check each of these for bulging where the rubber hose attaches to the convector. No bulging in a good thing. Assuming no bulging, you can drain/refill the Alde system yourself following instruction on this discussion: https://tab-rv.vanillacommunity.com/discussion/comment/164389#Comment_164389. I used the shop vac method with good results, others have made the pump setup. Either way this will cost you about $30/ gal of TF1 (the yellow stuff) max three gallons. You DO NOT have to change to the Romar (blue stuff) there appears to be no advantage to the new stuff. Mine only required two gallons and I completely emptied my system, removing all the convectors to repair the bulging problems. This dealer is just ripping you off.

Greenhil · May 2

Having read much of this epic discussion on replacing the Alde glycol, I’m still unsure about what people like me are doing whose T@B (2022 320 CSS) has the expansion tank behind the toilet. Having printed out and studied ScottG’s masterful instructions, I can’t see how I can put them in practice because of the difficulty of accessing the expansion tank. Am I missing something in the instructions or are folks with the expansion tank in this location using another method (like disconnecting the hose at the convectors)? Apologies if this has been covered somewhere!

ScottG · May 2

You're not missing anything, @Greenhill. Relocating the expansion tank to behind the throne is a relatively recent change. I'm not sure how many owners with that configuration have tackled a glycol change to date, but I'm curious to hear what others come up with.

Does your T@B have the double glycol drain? If so, I think you could use pretty much the same exchange process by filling and draining from underneath rather than through the expansion tank. This approach would actually be easier as you would not need to fabricate the expansion tank adapters.

pthomas745 · May 2

Can you show us what the tank looks like back there?

Mobean · May 3

I have a 2021 320S with expansion tank behind the toilet. I used ScottG's instructions last summer to replace my Rhomar glycol but modified the expansion tank connection with a #10 rubber stopper https://www.widgetco.com/products/10-rubber-stoppers-with-2-holes. It takes some manipulation but the rubber stopper keeps the connectors steady so it can be a one person job.

Image: https://us.v-cdn.net/5021717/uploads/editor/sj/rfefudqi5d0v.jpg

Image: https://us.v-cdn.net/5021717/uploads/editor/jr/m0jcgooqoeq3.jpg

You will need hollow punch to make the stopper openings large enough to fit the ⅜" OD toilet supply line connectors in ScottG's instructions. I purchased a hollow punch set from Harbor Freight to enlarge the holes in the stopper. The stoppers are inexpensive so by two.

Greenhil · May 3

Thanks for the responses Scott, Paul and Mobean. That’s an interesting adaptation, Mobean. I assume you got the adaptors situated in the tank by “feel” since there really isn’t room to look into the tank and see what you’re doing (photo below). I also wonder if, given the very confined space of the bathroom, the clear tubing could be lengthened so the pump and fresh glycol could be in the cabin of the camper- leaving room for a second pair of hands to keep the adaptors in place, if necessary.

However, all this may be moot because of Scott’s question. I do have what I think are 2 glycol drains - see photo. I don’t really understand why there are two. There’s no info in the Alde manual. And I don’t understand how I use these (without pump and adaptors?) to replace the glycol as you suggest, Scott.

ScottG · May 3

@Mobean, thank you for confirming the adapters can still be used with T@Bs having the expansion tank in the bathroom. Clever idea with the stopper, too--I might incorporate that the next time I break out the tools for a glycol change.

ScottG · May 3

@Greenhil, check out this recent post by @Robermcm. It explain how Truma uses the double drain stubs with their "bottom-fill" glycol exchange pump.

Conceptually, the process is the same as described in the DIY document, except the inflow and outflow occur at the double drain under the camper rather than via adapters inserted into the expansion tank. Note that for this approach to work, you need to tightly clamp the heater hose on the inside of the camper at a point right between the two drains. As you pump fluid into the "downstream" drain, it will be forced through the system and eventually flow out the "upstream drain." Just be careful not to pump so fast that you overflow the expansion tank in the process.

Greenhil · May 3

ScottG said:

@Greenhil, check out this recent post by @Robermcm. It explain how Truma uses the double drain stubs with their "bottom-fill" glycol exchange pump.
Conceptually, the process is the same as described in the DIY document, except the inflow and outflow occur at the double drain under the camper rather than via adapters inserted into the expansion tank. Note that for this approach to work, you need to tightly clamp the heater hose on the inside of the camper at a point right between the two drains. As you pump fluid into the "downstream" drain, it will be forced through the system and eventually flow out the "upstream drain." Just be careful not to pump so fast that you overflow the expansion tank in the process.

Thanks for the clarification and the link. Having read the thread, I understand the need for a clamp between the drains, but if you’re suggesting the two drains are different (downstream vs. upstream), how do I determine which is which? I’m assuming I can still use the pump you recommend and some sort of adaptor that fits snugly into the “downstream drain”in order to get the new glycol into the system. Correct?

ScottG · May 3

Good question, @Greenhil. Since I'm not exactly sure how the newer T@Bs are configured, I can't give a quick answer.

What you would have to do is trace the flow of glycol past the drain. Illustration 1 in the DIY guide should help. Note that glycol flows to the circulator pump first, then into the boiler body. As such, the downstream drain stub would be the one closer to the circulator pump.

Robermcm · May 3

there is a one-way ‘non-return valve’ in the Alde glycol boiler just after the gold auto air bubble bleeder on the top boiler hose. Not marked in my picture, but under the two sequential hose clamps to the right of the gold valve. There’s also a non-return valve as part of the hot water flow system, if you have that.

Pumping fluid will tell you pretty quick whether you guessed right, as you try to pump glycol into the tube and force it out the other tube. Here’s my own hacked up picture of the flow. I’ve seen better ones. Those two hoses that stick out the bottom of the floor don’t show but would be in the lower left corner of this illustration, connected inline with the ‘return from central heating’ pipe.

Mobean · May 3

@Greenhil looks like you don't need to go the expansion tank route but for those reading the thread, I position the exchange pipes in the correct openings in the expansion tank then slide the #10 stopper down tight into the expansion tank opening. A little dish soap helps the stopper slide. I do use longer hoses so I can be out of the bathroom.

R60us · May 4

Help....
I am trying to do a flush and fill of my Alde 3010 (2018 Tab 320s) but can't get the fluid to flow. I have made the adapters for the expansion tank and am able to pump some distilled water in the input line however the pressure increases and it becomes impossible to pump.
As I pump NO water is coming out of the return line.
I have tried to using a shopvac on the return line and it only sucked a small amount out then hydrolocks and will not pull anymore fluid out. It is sucking so hard it is collapsing the shopvac tank and overheating the motor...

I have also tried to turn the system on circulate but it doesn't seem to change anything. I can hear the pump click however it doesn't seem to let the fluid flow.

The expansion tank was drained with the plug under the camper and plug put back in.

It seems as if there is a valve in the system that is shut stopping the fluid from circulating.
What am I doing wrong?

Thanks all,
Rob

Robermcm · May 4

Glycol can only flow one direction. There are one-way valves that cause this. If you’ve used the system successfully before this flush, those valve are working and oriented correctly (reports of valves put in backwards in new trailers occasionally). I’d wonder if yer trying to pump the wrong direction.

R60us · May 4

The system was working prior to starting this. I also, switched lines to make sure I had the lines correct but still no flow

Robermcm · May 5

Hmmm.. The only places I can think of that would stop the flow are:
- the glycol jug itself not having a vent for air to come in as glycol is pulled out by the pump
- the one-way valve in the Alde boiler line
- the one-way valve in the Alde Flow tank, if you have the Flow
- some restriction in your pump/hose system

Out of ideas if none of those help. I’d want to see the pump gizmo pulling glycol out of the jug and into another clean container. Just to prove it’s not some broken gizmo.

Then maybe I’d want to open a bleeder valve (bathroom bleeder is up highest in the 400 and least messy for this hairbrain idea. Less clear on 320 locations) and try the pump then. See if you can get it flowing in a shorter section of the loop.

Since it’s a flush, have you first drained the old glycol out the bottom of the tab via the clamped red stopper tube? If empty of glycol I might want to open that up, Put a bucket there and see if I could pump all the way to that exit. It’s before the one-way valves, I think. Can learn something.

pthomas745 · May 5

When you pulled the glycol drain plug, how much came out? I would have to think about this a bit..but if you pulled the drain plug, it drained the glycol from the "lower hoses" in your system, from about the tank down to where the pump is.

If you are trying to draw out the glycol from the Alde return to the tank, there is really nothing to prevent that from happening. The Non-Return valve is the section of hoses directly after the Alde Bleeder Valve fitting on the side of the Alde.

I'm wondering how much glycol you started with, and if the glycol is already out of the trailer.

Howdy, Stranger!

Quick Links

Categories

Changing out the Alde fluid.

Comments