Changing out the Alde fluid.

jimcenname

@pthomas745 Quartzsite was very busy, lots of attendees. It's a funkie event, it took me a year or two to get used to it.

Freespirit

@ScottG, after flushing my Alde system per your very detailed instructions, I was able to complete the task of refilling the system with the Rhomar fluid.  Once again I followed your detailed guide and it worked like a charm. It took 2 1/2 gallons of fluid and about 10 minutes to complete. I must have been one of the fortunate ones, as after ten minutes of running the circulation pump on high and turning the Alde on, I experienced no air bubbles.  I did invert the pump as you suggested and had all my Rhomar in one bucket, so not having to stop pumping to place suction hose in a different containers of Rhomar may have helped avoid introducing air into the system. 

I have been running the Alde on propane only, electric only (1k and 2k) and propane and electric with the performance everyone expects from the Alde heater. 

For me, replacing the Rhomar fluid will be annual preventive maintenance along with everything else I do. 

Thanks for taking the time to understand the Alde system, putting a parts list together that is more economical than Aldes proprietary flushing system and then documenting the process.  Hats off to you!!

Cheers

ScottG

Thanks, @Freespirit. Glad to hear everything went smoothly!

MuttonChops

Basic Gravity Drain Only Glycol 'Refresh'

Just completed my first Glycol 'change'.
T@B purchased about 4-years ago have added .5 gallons or so glycol during that usage period.

After reviewing the "DIY Alde Glycol Exchange" PDF reference guide procedure, decided to avoid that more complex project so have used a modified gravity drain & refill.
 - - Started with Expansion Tank a little above the min-mark,

 - - Run Alde to warm glycol to 90F, shut-down, then drained around 1 gallon of old glycol.

 - - Refilled the system with 1 gallon of new** glycol.  Expansion Tank near max-mark.

 - - Ran circulation pump for an hour or so.

 - - Repeat of gravity drain and refill.

Am assuming;
= worse case I've  got  a 50% old -with- 50% new glycol mix
=   best case I've  got  a 25% old -with- 75% new glycol mix.

I'm no chemist or metallurgist but I'm fine with this approach.  Right or Wrong as it maybe.

** Original 'century' heat transfer fluid glycol type

qhumberd

What I have learned from this thread is that the glycol change is needed to provide new anti corrosion protection which we assume degrades with time, and that there may be a grounding issue that causes a current flow resulting in corrosion at the connectors. There may another cause of the problems owners have reported yet to be discovered. I have done the first remedy with the original glycol after a thorough flushing and I plan to do the second before this camping season once I get the camper out of storage. I think that a partial replacement, as described by @MuttonChops, can likely help with the anticorrosion protection, but in truth everyone has to act in a way that they can live with, right or wrong. The more technical members of the forum have given us lots of choices but no definitive answer, and we continue to learn as time goes on.

keningalls

I have a 2019 Tab 320, I checked the PH of the glycol and it was 8.0 so still good after 3 years, the factory says to change every 2 years but that is very conservative, Alde has to assume that the owner is using the system 24/7 to get down to 2 years. Heat breaks down glycol with use, so if you do not use the Alde system very much it will last a lot longer. I'm just going to drain what comes out each year and put in a new  of the same Century TF-1 fluid and test the PH each year to make sure the PH stays above 7. If the PH drops below 7 the glycol becomes acidic and will start to eat out the aluminum heat exchanger within the alde until it fails. 
If you want to drain the whole system by gravity add another drain just like the boiler drain through the floor, install it on the other side behind the passenger tire wheel well, cut it into the return hose from the passenger radiator this will drain the radiator and piping on the passenger side. I would do this as its very easy to do, just order the tee drain from the factory with a couple of hose clamps drill a 1/2" hole through the floor and install it.
When you cut the glycol hose make sure you have an aluminum pan underneath to catch the glycol alternately you can kink the hose on both sides of the cut to install the tee.
Once installed all you have to do is open both drains and then fill it with the same glycol and you are away to the races.
 I'm first going to just watch the PH and add about a gallon new  each year I think for my case it will be all I need, if not I will put in the drain. What's important is the PH level not so much time.
Good Luck

Sharon_is_SAM

I believe there was corrosion in units where the glycol pH was unchanged.

fstop32

I second your comment @Sharon_is_SAM.  My T@b's pH was "within the given range" and I had corrosion at every aluminum to hose connection beyond the boiler which resulted in a complete rebuild on my 2015 (see thread "Corrosion of Alde Convectors).
I would recommend visual inspection of all the hose-to-convector locations looking for the telltale bulges at least as often as you check the pH.
@keningalls, I intuitively went with your passenger side drain idea when I put in my new hoses.  By eliminating the small convectors in the driver side "electrical/converter" area I was able to run all my hoses so they would drain with no pockets of glycol remaining in the system (sans boiler).  I even backfill my system from that new drain location.  I also changed over to the new Rhomar glycol at the same time.

ColinsTab400

Hi all,  Thanks for your help.   I used all the suggestions above and used this process attached to successfully change the transfer fluid in my 2019 400.  I made a "service pump" to do the transfer using the attached pump.(hoses and buckets from Ace Hardware.  This pump runs at the same rate as Alde's service pump with both pumps running. ( they have 2)
I opted to use century fluid since it has a proven history and availability.  Glad I did that since now the Rhomar fluid has a 2 year change recommendation

pump purchased on Amazon... 
pipe connections had multiple sources...  fastest delivery was by Walmart

Good luck to anyone doing it...  

BrianZ

Ok, so where do all our DIYers here purchase their Rhomar for doing their own fluid exchange from the old glycol?  If multiple options, which is most economical? Price?   And what about a source for the pre-exchange wash solution (hydro-solv?)? 

bergger

You should be able to purchase the Rhomar from a dealer.  I bought ours from Holiday RV here in Colorado for $26.99 a gallon.  When I purchased it the salesperson said that NuCamp was raising the price soon so now it is most likely more expensive. 

ColinsTab400

FYI….apparently the Rhomar fluid is now recommended to change at two year intervals….  May as well stick with century since it’s more readily available 

Parlando

I have Two questions.  I have a 2015 320 Outback.  I've contacted a dealer who says that they flush out the old fluid with plain water (not distilled) and then add the new glycol.  What is the reason to use distilled, and might this be okay.  Also, I've read some accounts of flushing out with 25 gallons of water. Does all the flushed water need to be treated as toxic waste, ie, not spilled on the ground nor poured down municipal water systems.

bergger

I used distilled water when I did my own flush. But I don't think it is absolutely necessary. Airstream just uses "clean" tap water. I think the idea behind distilled water is to not introduce any minerals into the system. But I'm not sure it's really necessary as the new glycol should push out the vast majority of the water. Any residual minerals probably won't make a difference.  I used 15 gallons Of distilled water to flush mine out. And yea I captured the contaminated water and was able to dispose of it for free at our local land fill which was nice.  

Denny16

Yes, the old glycol needs to be taken to a hazmat disposal site.  As for the flush water, it does contain a small amount of glycol, so proper disposal is also advised.  

Cheers 

Dutch061

Actually, since the old glycol is propylene glycol (same as used in an automobile) you can probably take it to your local auto parts store. They accept used motor oil and anti-freeze at no cost to you in most areas.

Hint do not tell them the used glycol isn't from an automobile.

Brad

Parlando

Thanks! @Dutch061 and @Denny16 and @bergger.

cottonmouth

I had my Alde fluid in my 21 400bdl switched at Ucamp 21, so am coming up on replacement time. I've done a little research and found a method on the Airstream forum that seems very straightforward and simple. He said he learned it from a Truma tech and it worked for him. There is no external pump, you use the circulating pump on the Alde.

• You make the tube with toilet pipe and a stopper, and attach 1/2" clear tubing to run to a 5 gallon bucket. 
• The stoppered tube is inserted into the return hole in the reservoir (I believe that's the one directly under the cap, and not the offset one. I'll need to verify). 
• Open 5 1-gal distilled water jugs and have them close at hand
• Place the end of the clear tubing in the bucket and turn on the Alde panel. Ensure heat electric/propane is off, and turn the pump to continuous circulation.
• The glycol should start pumping into the bucket. 
• Pour distilled water in the reservoir to keep the level falling too low. This will keep air from entering the system.
• Continue pouring the distilled water until nearly all of the 5 gallons is poured (don't want to overflow the 5 gallon bucket) and remove the tube from the reservoir.
• Allow the circulation pump to run the distilled water through the system for a few minutes to flush. While it's running, prepare 5 more gallons of distilled water in jugs.
• Put the end of the clear 1/2" tube in another 5 gallon bucket and insert the stoppered tube end in the reservoir return hole again. Follow the above steps to flush another 5 gallons of distilled water again. You can do it again, but 10 gallons is probably sufficient, especially if you've already had the rhomar switch done.
• Pour rhomar into the 5 1 gallon jugs.
• Add the rhomar like was done with distilled water. Keep adding until all of the water is flushed.

I plan to try this later this fall. Any comments or concerns from the gallery? I welcome all insight and expertise!

ScottG

I think this could work. From the description it sounds like a fundamentally similar approach to what is described here. The biggest difference is that rather than forcing new fluid through the system with an external pump (manual or electric) and a second toilet riser/stopper gizmo, this feeds the new fluid in via gravity and moves it with the Alde's circulator pump.

I am a little skeptical that this approach would sufficiently rinse the system if the objective were to change the brand of glycol. I think that would require multiple flushes (until the rinse water was absolutely clear), followed by flushing with an excess of glycol (until the new glycol was no longer diluted.

If I were actually rinsing the system and changing the brand of glycol, I would be inclined to incorporate a draining procedure as well to reduce the amount of flushing needed. And, as the aforementioned document notes, thorough draining can be a little tricky as both e the Alde and the T@B's convector loop have low spots that will not drain by gravity alone.   

cottonmouth

Thanks for the feedback. Our local RV shop wants $600 just for the labor - fluids are extra, so I'm looking for an efficient way to do it myself. I was all prepared to purchase the pump and parts to build out my own service pump when I saw this method. It seemed logical. I don't see it as a gravity flush. The fluid is actively circulating through the full system with the Alde circulation pump. And allowing the distilled water to circulate through the system for several minutes between fresh distilled water flushes seems like it would provide a good flush/rinse. I've already had the exchange of fluids (by Truma at uCamp 21), so I'm not too worried about the flush

My hesitation/questions arise in that Alde/Truma use a service pump to exchange fluids, and not this method, which seems simple, cheap, and effective. Although supposedly this method was taken from a Truma tech, who may have been taking shortcuts like techs are known to do .  Since I've already had the flush and exchange, I think it should be effective. I have a few months to do more research and decide. In the meantime, I welcome the feedback!

ScottG

@cottonmouth, yeah, the "gravity" is when you manually pour the fluid into the reservoir.  :-)  I agree the circulator pump is doing the work and, based on my limited experience, it does seem up to the task particularly if you increase the pump speed.

If you're just swapping out with the same glycol, and the glycol doesn't look or smell bad, I'm not convinced of the need for the distilled water rinse and associated dilution you will need to contend with. When I exchanged my Century glycol a couple years ago, I flushed the boiler with water, and even though I drained it before refilling, I still think I had a little dilution from the residual fluid. Assuming I don't switch to Rohmer, next time I will just push the old glycol out with the new and call it good.

bergger

I agree that if you've done the switch to rhomar already it is not necessary to flush the system again with water.  I did the switch last year and next year plan on just putting in new rhomar.  When I did mine the total cost was about $155.  I used a 12v pump to pump in the water and rhomar in addition to using the Alde pump to help circulate and pull the fluid through the system.  The 12v pump was literally $12 on Amazon and for that price I think it is worth using the two pumps instead of just the Alde pump.  I pumped "in" the fluid and used a shop vac in the return line to suck out the fluid.  It might be a bit tricky to hand pour the water or glycol in the tank as the process is in full swing.  At least in our 400 it would not work at all due to the location of the tank.  Fluid moved faster than I anticipated and I was glad to be using the pump and shop vac to add and remove fluid.  Things could be turned on or off immediately with the push of a button.  But it did take two of us, one to make sure the tubes stayed seated in the reservoir and another to manipulate the pump and vacuum. 

Just remember I found it important to open the bleeders during the process to make sure the old glycol was flushed out of the bleeder lines.  This was important in the line behind the bed and behind the passenger side dinette seat.  In our 2021 400 both of those had bleeder lines approximately 12-14" long and I found the old Century fluid was just sitting in them and not getting replaced with Glycol.  Once opened up they of course fill nicely with rhomar.  Each trailer year and possibly trailers in the same model year may be different so I recommend locating all your bleeders and finding our which ones have tubes attached to them.  I know in the 2022 400 they added a bleeder tube to the valve under the kitchen sink so that model probably has 3 tubes vs my 2.  

But this other method just goes to show that there seem to be several ways people can do it without paying all the money dealers want.  

cottonmouth

Bergger, you're probably right about being able to hand pour the fluid into the reservoir and keep up with the circulation pump. It's pretty tight in that porthole. A funnel might help. And I figured I'd have the wife by the panel to turn off the pump if necessary.

I had wondered whether it was necessary to flush  with water even after the switch to rhomar. It seemed like overkill to me. I think I'll just displace old rhomar with new when I do it. Should be a fairly quick process. About how many gallons of glycol are in the system? 

qhumberd

@cottonmouth and @bergger I will be interested to see if the circulation pump can move the glycol out the reservoir as outlined above all by itself. I used the 12V submersible pump like @bergger but disconnected the hoses from the reservoir and attached my fill and return tubes directly and found the little pump moved about 1 gal per minute or so into my drain bucket. I used the circulation pump to get the air out of the system after the exchange. There was only one bleed valve in the bath in my version.

I copied what I posted back then on the amount of glycol for my 2019 400:

I used the entire 4 gallons of Century I got from Amazon, and may have flushed more through than I needed to as I got a clear color change at 2 1/2 gal but I put in an extra gallon to be sure (3 1/2 gal total fill) before I removed the hoses and reattached the reservoir. That left me only 1/2 gal to burp the air out of the system and I had just enough!

justdoit70

Holy cow ,I love this idea it seems so straight forward and in my humble opinion this looks like the way to go. I will be doing this come March. Question is the toilet pipe like a hard toilet supply line ?
Thanks, Ed
2021 400 boondock solo
2016 Taco sport double cab 4x4
NEPA

MarkAl

I like the concept, but NuCamp puts the reserve tank in such hard-to-reach places it could be tough to get to the bottom tubes. Behind the toilet in the 2021+ 320s for example. I've one more year to plan how to do it.

bergger

That is precisely why I used an inexpensive 12v pump and the shop vac method. I still had to unscrew the reservoir from the wall so I could get it in a position to firmly seat the tubes into the return and outflow ports but it worked well.  Having them firmly seated is key to getting the old century out. If not seated tightly you end up getting a lot of mixing of the water and century fluid and the whole process just takes more water and time. The same goes for when pumping in the Rhomar to push out the water.  Trying to pour the fluid in, on the 400, would have been difficult for me. I like the pump method. 

cottonmouth

I have a right angle offset funnel that should make pouring fluids doable. I think the bendable pipe with an appropriately sized stopper should work to get in that tight space too. I'll update when I give it a try. I still have until late summer/early fall before I'm scheduled to exchange the "old" rhomar. I'm still searching around for a source for the rhomar water in southeast Louisiana.

Freespirit

After replacing just about everything except the ALDE unit about a year and half ago (hoses, convectors, reservoir tank, check valve, circulation pump) due to corrosion of my convectors, I decided to do a flush and replace the Rhomar fluid today. The first set of pictures are of the one and a half year old Rhomar and pH test strip. The second is new Rhomar and pH test strip. 

FIRST:
SECOND:


Interpretation is subjective, but it appears to me the older Rhomar is a little lighter in color and pH closer to 8 than 7. The newer Rhomar appears ever so slightly darker and the pH real close to 7. 

I did not remove any hoses to visually inspect the convectors but I did not notice any bulging at any of the convectors. I will remove and inspect next year. 

RMo

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?