Changing out the Alde fluid.

Freespirit · March 2023

@RMo, I did NOT use a shop vac for the original flush to remove the Century fluid or to refill the system with Rhomar the first time. This time I did Not use a shop vac either. Both times I followed the DIY Alde Glycol Exchange for T@B Travel Trailers(v1 introduced May 2021) by @ScottG. In my opinion, Scott did an excellent write up to efficiently and economically way to flush and fill the Alde system.

You asked, my thoughts, FWIW: if you are going to drain/ flush your system of Century and replace with Rhomar the only way to come close to removing 100% of the Century fluid(IMHO) is to remove hoses and convectors. This is even true if you flush with distilled water until it runs “clear”. There are several low spots in the system that retain “fluid” and the only way to get it out is to disconnect the hoses from the convectors and very carefully capture the residual fluid. Even after I did a total flush until the water ran “clear” (15 gallons distilled water), I disconnected the hoses and carefully removed hoses from the convectors and captured an additional 2 quarts of very lightly colored yellow fluid(distilled water and remaining Century).

As for filling the system, here again I did NOT use a shop vac. I used Scott’s method. If I did not use Scott’s method, I would probably just use a funnel/hose extension combination and add the new fluid thru the reservoir tank. Then making sure the propane is turned off, the Alde unplugged, and the Alde set to circulation vs therm, turn the circulation pump up to 5 for about 15 minutes while keeping an eye on the reservoir to maintain the appropriate level. Once I feel most of the air is out of the system set the Alde back to therm, plug the Alde back in and turn the propane on or use shore power, set the thermostat and see how she works.

bergger · March 2023

RMo said:

bergger said:

That is precisely why I used an inexpensive 12v pump and the shop vac method. .....

I'm curious as to whether you tried to use just the shop vac to suck the new fluid in, without the 12v pump. I'm wondering if having the shop vac in a low position and having the bucket of new fluid elevated might provide a gravity/siphon assist and be enough to replace the fluid without a separate pump. Thoughts?

@RMo no I did not try that. But as you can see by reading all the threads on fluid changes that there are several ways to do it and each has their preferred method. You can do the whole process without a shop vac or pump, by just pouring fluid in and using the Alde to circulate the fluid. However I really like the way I did it by using the Alde pump, the shop vac and the 12v pump. As long as you have two people it's quite easy. My wife operated the switches for the 12v pump and for the shop vac while I told her when to turn things on and off as I held the tubes in place in the fluid tank. I figured I already had the shop vac and since the pump was only $12 why not use all three. It allows the Alde pump to circulate the fluid, the 12v pump to easily pumps in the new fluid and the shop vac to removes the old. And no need to disconnect any Alde lines.

BrianZ · March 2023

Glycol Replacement After Hose Repair

Over in the parallel topic, "Corrosion of Alde Convectors" I recently wrote about the failure of one of my convector-hose connections that I fixed by adding a second set of clamps to all convector-hose connections. However, I still need to add glycol following the leak, and it's been 1.5 yrs since our last change, so I may as well replace whatever glycol remains.

After I had previously installed a 3-way valve, I anticipated that any future glycol changes would be a simple matter (should still be true but this time I have air in the lines to deal with) of opening the drain & pushing out the old glycol with fresh glycol added from the valve, then closing the drain & switching the valve to refill the drain line & tank - see diagram below (thanks again @ChanW for letting me borrow it).

However, I don't really know exactly how much glycol remains, and I'm guessing that the portions of the pipes I colored black would likely be air after losing some of the glycol. Opinions? Regardless, I will have 3 gallons of new glycol (the old yellow stuff), which is about one more than what the whole system holds. I plan to just pump 2G's on through to fill and hopefully remove most of both the old glycol & air in the lines by using an external electric pump to inject the new glycol, plus an additional half G for good measure. My only question is whether I should pause after the 2G's to run the Alde pump to bleed air out before adding more? I wonder how much the expansion tank max level plus drain line holds? Less than a quart, maybe?

By the way, I've added some measurement notes in the drawing for the height of our tank, upper convector hoses & Alde output hose, measuring from the floor. I was surprised that the rear convector upper hose was actually slightly lower than the Alde upper hose, so it's really not a high point in our system, just in that particular half of the convector loop.

sequimite · April 2023

@ScottG, is v1 May 2021 of your DIY Alde Glycol Exchange document still the latest. I'm preparing to take the plunge!

sequimite · April 2023

I had one more thought after studying the system diagram in the @ScottG DIY Alde Glycol Exchange document. Would plugging the outflow at the reservoir with a stopper and blowing into the existing low point drain instead of the disconnected hose at the non-return valve clear glycol from the convector loop without disconnecting any hoses?

Sorry if this has been covered before. This topic thread is super informative, but man is it long!! And I'm adding to it.

ScottG · April 2023

@sequimite, yes, that is the most current (and only) version of the document. Somewhere I have a few notes for minor edits, but have yet to actually tackle the task.

In theory I think your idea for clearing the convector loop could work. However (as I suspect you have already determined) you would have to do this with the outflow adapter and waste collector in place since the existing low point would be commandeered for air injection.

You would also have to be forcing air through a longer loop including the circulator pump, boiler core, and air bleeder assembly. I have no idea if/how this might impede the process.

From my perspective it still seems easier to just disconnect downstream from the air bleeder and use the existing drain, but YMMV. If you give your method a try please report back how it turns out.

BrianZ · April 2023

Glycol Topoff-Flush

In my previous post above, I had estimated our glycol leak from a hose that slipped off of a convector had lost about a half gallon of glycol. Now that I was ready with 3 new gallons of glycol to flush & refill, I figured the first step was to confirm the amount lost, by refilling the system. It did indeed take about a half gallon to refill, and now I could move on to flushing the system with new glycol.

A few years ago I calculated the volume of the Alde glycol hoses from their length & diameter to be just over a gallon, or a bit over 2G total in our Alde system, including internal & external tanks. So, with 2.5G of fresh glycol remaining, I could flush 2G through using my 3-way valve previously installed in the hose between the glycol drain and the pump, in order to push out the remaining old glycol via the drain..

Before flushing, I set the 3-way valve to isolate the drain side of the valve, so I could drain, catch, & measure that volume in the expansion tank & drain line. Then I opened the glycol drain valve under the T@B to catch and measure about 1/3 G..

I could now flush the system, while saving at least that amount (1/3 G) of fresh glycol to then switch the 3-way valve 180 degrees to backfill the drain line and refill the expansion tank..

This left me with about a half gallon of fresh glycol. Next time, assuming no more major leaks, I should be able to do the flush & refill with just 2G of glycol.

However, if prices come down, maybe I'll go with the Rhomar glycol & the extensive flushing required to make the switch. For now, after a leak, I just wanted to get our system back up & running with minimal fuss. I also know the extensive cleanup & treatment for corrosion that I did 2 years ago is still holding up well.

sequimite · April 2023

Finding the Rhomar Hydro-Solv 9100 flush agent in less than a gallon has proven to be impossible. I asked Alde if other flush agents are safe and approved. Here is that dialog.

Q: I want to flush my Alde 3010 system. I want to use Rhomar Water Hydro-Solv 9100, but one must buy a gallon. Since the flush takes just 6 oz of Hydro-Solv and, as I understand it, is recommended every 6 years, it's way too much product. What other flush solutions are safe for my system--vinegar solution, Fernox, etc.?

A: I spoke with a technician and they use RhoGard to flush the system. In no way do they recommend using any other products that you listed.

I now own a lifetime supply of Hydro-Solv 9100.

pthomas745 · April 2023

All the questions to NuCamp about the Alde and the glycol are a closed loop. You must use Rhomar. You must use a Truma product. That is all.

Maxcamp · July 2023

@ScottG et al, appreciate greatly the shared instructions and experiences.

Just did the two year interval Rhomar in-kind swap today on our Jan.2021 320s.
Handpump method (harbour freight cheapie), two copper tubes with bungs plugged into reservoir outlets.

Necessary to invert pump or pumping tons of air.
10 to 12 turns of Teflon tape over 3/8 soft copper tubing to get the amazon bungs to hold tight. Was concerned they might stay behind in reservoir upon withdrawal of tubing system. Hose clamps as stops to keep bungs from sliding up when seating.

Tried pumping into reservoir port leading to alde pump but 100% resistance and no flow back from reservoir radiator port.

Re-read Scott PDF narrative, flip flopped pumping port selection and quick success.
Very clean waste coming out

Another surprise, the alde circulation pump was on lowest setting, had never heard it run. We had poor heating performance with superheated rear bed area.
Bumped up to 5 for air bleeding via reservoir and then set to middle at 3. Now can track its use audibly.

2 gallons left in 5 gal pail purchased on account from my hvac supplier for 189.
2 inch lid screwport means did not open pail lid. Will it keep another two years?

nbrandt · July 2023

I knew I needed to get this changed in my 2021. I was low on fluid (troublesome - where is it going?), but of course one is not even able to buy the old fluid.

Took it to the RV Dealer in Portland where it was purchased. They almost "scolded" me for not getting it changed yet. I talked with the service manager about changing it myself. He commented that there was a big learning curve even for them and that all of the old had to come out. So I scheduled the change which is going to happen August 5 - at a proposed charge of $850! That made me swallow a bit.

I said, "So the company is requiring this change of fluid."\ Any chance that any of that cost is a warranty item?" He said he would check. I do not have high hopes.

ScottG · July 2023

Thanks for the report and additional tips, @Maxcamp8. I'm glad to hear the process worked well on your 2021. I've wondered if the models with the reservoir tank in the bathroom would provide any unexpected challenges.

ScottG · July 2023

@nbrandt, since changing the glycol is considered "routine service" I would also be very surprised if it was covered under warranty.

That said, I suspect your dealer might be over-dramatizing things a bit in the interest of generating an $850 bill. The Alde may be a bit complex for a piece of camping equipment, but it's not a rocket ship. Just my $0.02, YMMV!

manyman297 · July 2023

Question for those who have done this...do you find it easier to leave the reservoir intact and use the copper tubes and stoppers or is it easier to remove the entire reservoir and use Pex fittings (I believe that's what I saw somebody use). It would be nice to have access to the inlet/outlet piping directly but if removing the reservoir is a pain then I'll stick with the copper pipes.

qhumberd · July 2023

In my 2019 I first removed the reservoir to get access to the inlet and outlet hoses and then decided that since I had the room next time I could just remove the hoses and attach to my flush hoses and electric pump. I used a 1/2 inch hose and 1/2 to 3/4 PEX adaptor and a little tape and a worm clamp to seal the hoses. If you can get the hoses off the reservoir easily that makes it go faster in my opinion.

If you are careful, your can just pull the hoses off after loosening the clamps down the hose. Hose ID is few mm more than 3/4

As mentioned, this could be done leaving reservoir on the wall in my 2019, where it is in the closet. You need to completely drain the reservoir first.

Here is pump I used. Steady flow and pumped about 5 gal in 3 min.

Image: https://us.v-cdn.net/5021717/uploads/editor/ax/b31p4r2x64nt.jpg

Maxcamp · July 2023

Thankful for the tubing/stopper method, or I might have ended up detaching sink and other caulked in items.
The recommended rubber stoppers worked great. Tape on copper tubes critical for tight seal so you don't end up just pumping reservoir higher, as my first attempt did.

@manyman297 ,

I too thought to pull reservoir but found inadequate clearance to get to to hose clamps or screws, using hands and flex shaft drill extension.

On our 2021 320s, this system _had_ to have been installed from front of camper before outside skin went on.

Your 400 model may be set up differently.

manyman297 · July 2023

One last question. How much fluid should be replaced in a 400? I know @ScottG manual mentions around 3-4 gallons but is this just an estimate? I’d hate to do the service and only get partial fluid out of the system. Are there official numbers on this?

Sharon_is_SAM · July 2023

I have an email from nuCamp from 2018 that says 4 gallons for the 400 and 3 gallons for the 320.

Horigan · July 2023

I recall four gallons when I sucked it out using the shop vac method on my 2019 400 with Alde Flow.

manyman297 · July 2023

Awesome! Thanks for the info @Sharon_is_SAM @Horigan

manyman297 · August 2023

Quick update. It looks like @qhumberd method of pex fittings might be the easiest method for me. There's enough flex in the lines that I probably don't need to remove the reservoir. The stopper method seems more risky (at least on paper) because it seems the stoppers could work themselves loose but maybe I'm wrong.

I removed the panel behind the driver-side bench to see if access was easier that way but it isn't. One thing it did allow me to see was the connections to the convectors and they look (and feel) fine.

One question I had was about the inlet and outlet pipes. I'm assuming the connection in the reservoir with the large bulb is the inlet? Just looking at @qhumberd photo and his shows this.

Also, in @ScottG writeup on the fluid exchange he notes that the hand pumps may have lubricating grease in them and to try and clean it out as best as you can. I ended up getting the 12v pump similar to @qhumberd and wondered if there is the same lubricating grease in this. It seems especially important to check since this pump will be pushing the fluid into the system and bringing anything it catches along the way. Any thoughts?

ScottG · August 2023

@manyman297, I agree that in the 400 that removing the reservoir and attaching directly to the glycol hoses is probably the best approach. In the 320 this would be more difficult as the the bottom of the reservoir is usually inaccessible.

You are correct about the reservoir connections. The pipe with the large bulb (directly below the filler cap) is where glycol returns to the reservoir from the convectors.

I'm not sure about grease in the electric pumps. It wouldn't surprise me if they contained some lubricant, but I'm not aware of anyone who has used an electric pump has mentioning it being a problem. Maybe someone else can chime in with a more definitive answer.

bergger · August 2023

When I did our change over I kept it real simple using the shop vac/pump method. I did not use any pex fittings or rubber stoppers. I also used a $12 12v pump from Amazon. With two people this is possible. I removed the tank from the wall which allowed me to access it a little easier. I simply held the line pumping in the fluid as tight as I could in place and did the same with the vacuum line. I then told my wife when to turn the vac and pump on and off. This method was very simple and uncomplicated but absolutely requires two people and also requires you stretch and loosen up your neck and shoulders prior to beginning the procedure!

qhumberd · August 2023

@manyman297

Yes it is important to verify the flow to and from the reservoir, as there is a check valve in the system. Below the arrows show flow direction.

The enlarged area closer to the middle of the reservoir is the glycol from the Alde convector loop TO the reservoir and in my rig comes from the last convector in the bath.

The hose with the smaller connection goes FROM the reservoir back to the Alde unit to be reheated.

Image: https://us.v-cdn.net/5021717/uploads/editor/76/z4zxl6v8xgfe.jpg

So simply stated, you pump INTO the hose on the R below, and this forces the glycol thru the Alde and then thru the convectors and OUT the hose on the L below.

Image: https://us.v-cdn.net/5021717/uploads/editor/g5/bo62i6b0efwg.jpg

My pump was designed for all liquids including diesel per the label and as such I can't see much grease would be in such a pump as the fluid would dissolve that right away.

Good to see your connections looking good. I'll check mine for my 2 year flush and refill (with Century again) in a few weeks and report what I find.

Best wishes

manyman297 · August 2023

@qhumberd Thanks for the info! The 12v pump I bought actually comes partially apart and I don't see anywhere that grease (at last in bigger amounts) could reside. It's a simple electric motor. Tested it yesterday and it works really well and has the same specs as the one you posted. I'll be doing the exchange this Saturday and I'll report back on how it goes.

manyman297 · August 2023

Tackled my gycol rhomar-to-rhomar water exchange (not a flush) this weekend and I'm happy to report that it was MUCH easier than anticipated. If you're in the least bit mechanically inclined this exchange is a breeze. Thanks to @ScottG for writing up an amazing how-to. This served as the basis for my process.

Ironically the exchange itself went smoothly but I had a helluva time getting the clamp connectors back on the reservoir tank. I ended up having to remove the tank (easy enough) to give myself more room to move around and get my pliers on those clamps. In hindsight I should've just replaced those with the worm clamps I bought at Home Depot. The next time around I'll just swap them out.

I also initially had an issue with the 12v pump I bought. If anybody decides to buy one of these off Amazon (go a few posts up and you'll see the one @qhumberd used...mine is the same one) I highly recommend that you glue the outlet of the pump to the main body. The force of the pump actually blew the top of mine off sending glycol splashing everywhere. I used some Gorilla tape to remedy the situation but will need to just glue it on.

I also had a little problem getting the pump to prime. I was getting a ton of aerated fluid coming through as well as huge gobs of air but eventually it started to work. Just have patience. The air you introduce into the system will be flushed out the other end.

For the initial gravity drain below the trailer I was able to get out maybe 1.25 gallons of glycol (see below).

Instead of using 3/4-to-1/2 pex reducers I bought flex pipe elbows (the kind you use to connect flex pipe to sprinklers) and wrapped the threaded end with gorilla tape to help it form a tight seal (below). These ended up working great and were closer in diameter in size to the Alde hoses than using the pex reducer...and cheaper.

Image: https://us.v-cdn.net/5021717/uploads/editor/y1/didlk05vznnq.jpg

To help aide in draining of the fluid I placed the waste bucket outside on the steps. I found this help pull the fluid through the system more easily due to it being so much lower than the reservoir tank (below).

Image: https://us.v-cdn.net/5021717/uploads/editor/27/tswhrwj12ije.jpg

Belos is the 5-gallon drum I purchased through Miller Trailer Sales. $250...ouch.

Below you can see the connections. Left is the output and right is the input.

And here is the entire pump assembly. It came to about $35-40 dollars which kind of surprised me but it'll be used for the next exchange. Now if I can just find reasonably-priced glycol I'd be set.

In the end I pumped about 4.25 gallons of glycol through the system in maybe 5 minutes. Ran the Alde's pump (Keep in mind there's a pump on the Flow tank...that isn't used at all for this), topped off the tank a couple of times and listened until I couldn't hear any air moving through the lines. I've yet to actually test the heat so I'll report back if I run into any air bubble issues.

In the end this was an extremely easy process. I had just built it up in my head. I realize this could all fall apart when I go to test the Alde and it doesn't work but you're simply removing old fluid and putting new fluid in. Not much you could actually break here just be mindful of not introducing any foreign contaminants into the mix. Flush your pump with water prior to using it and work SLOW. Glycol can be messy so put down towels and bring a roll of paper towels with you.

In total with the trouble I had with the clamps it took me 2.5 hours. Half of that time was wrestling with the clamps and cleaning up glycol when the pump exploded.

Mobean · August 2023

Encouraging so many are performing the exchange without issues. What are you doing with the used glycol?

manyman297 · August 2023

Mobean said:

Encouraging so many are performing the exchange without issues. What are you doing with the used glycol?

Good question. I could drive it out to our county dump. It sounds like flushing it down the toilet is a no no. Just need a lid for my bucket and I taking it to the dump isn't a huge issue for me.

Mobean · August 2023

This is from the SDS on the Rhomar Water website. Sounds like proper disposal will depend on local municipality.

Image: https://us.v-cdn.net/5021717/uploads/editor/4z/uc09oarj7bd9.png

qhumberd · August 2023

@manyman297 glad to see another successful service on the Alde. I do wonder if running the Alde Flow pump is needed to move any glycol that provides boost heat to the Flow tank? If I understand the system the Flow pump only runs when the hot water icon is selected at the max level (designed to provide continuous hot water for 30 min for say a shower)

As far as the pump:

I also initially had an issue with the 12v pump I bought. If anybody decides to buy one of these off Amazon (go a few posts up and you'll see the one @qhumberd used...mine is the same one) I highly recommend that you glue the outlet of the pump to the main body. The force of the pump actually blew the top of mine off sending glycol splashing everywhere. I used some Gorilla tape to remedy the situation but will need to just glue it on.

I suspect this is a manufacturing issue as I have used that pump multiple times for water transfer etc. with no issues. I would send it back for a replacement.

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2019 T@B400 Boondock Lite "Todd"

2019 T@B400 Boondock Lite "Todd"

2019 T@B400 Boondock Lite "Todd"