Changing out the Alde fluid.

manyman297 · August 2023

Didn't know that pump was for the boost setting. When I got into the Alde compartment I was initially stumped by the two pumps since I was expecting to see just one.

Yeah, my guess is the brand I got didn't glue the top on. I can't imagine it's just simply a friction fit as the force coming out is much stronger that you think.

otr_320 · August 2023

Wow, this thread contains an immense amount of useful info from some very knowledgeable, skilled folks! Special thanks to ScottG for his input and time. I knew absolutely nothing about the operation or maintenance of the Alde system 2 days ago. After quite a bit of reading, not feeling nearly so intimidated now.

On our '23 320, access to the rubber hoses underneath the reservoir (behind the toilet) is very difficult. So far, I've read through 17 of the 29 pages of comments. For now, we're leaning towards using Gregndeb's procedure which uses "rubber stoppers" to access the send/return ports at the bottom of the reservoir (no need to directly access the hoses underneath the reservoir).

Had a few questions to make sure we have a clear understanding of how his procedure works:

1. First off, is there any way to accurately identify which port at the bottom of the reservoir is the send, which one is the return? I'm assuming this is important due to the one-way, backflow valve located in the system.

2. Is the following reasonably accurate? Using a rubber stopper to maintain a good seal at the send port at the bottom of the reservoir, an RV-type water pump (we have a spare Shurflo) would push new fluid through the entire Alde system via this send port. At the same time, another rubber stopper connected to the return port would transfer old, used fluid to a nearby container. It's my understanding there's no need to open any ports or disconnect anything to accomplish a full drain and fill using this method (outside of making sure the reservoir remains empty during the drain & fill procedure).

3. I assume there may be a chance the fluid color for both the new and old fluid may be very similar in color, so one may or may not know how much fluid to send/push through. If that's the case, should we pump, say, 3 gallons of new fluid and call it a day?

4. The fluid in our 320 is blue/green which I assume is 2-year fluid. Has anyone found a stateside source for the 5-year fluid (red?)?

5. If we do find a source for 5-year fluid, is there a general agreement on just how much distilled water needs to be sent/pushed through the system to fully flush the 2-year fluid before filling with the 5-year?

Lastly, I've heard the red "flow" tank option mentioned. I don't believe our '23 320 has this. Is this part of some option package, or did NuCamp randomly install these flow tanks in some units and not in others?

Thank you!

Sharon_is_SAM · August 2023

Are you sure your 2023 model has the Century glycol? TaBs manufactured after 1/4/21 all have the Rhomar.

otr_320 · August 2023

Sharon_is_SAM said:

Are you sure your 2023 model has the Century glycol? TaBs manufactured after 1/4/21 all have the Rhomar.

I could be mistaken. Fluid is blue/green in color. Manufacturer/Production date on our '23 is 12/2022. What color is Rhomar? Century? Thx!

bergger · August 2023

Yes don't be intimidated. It's actually a very simple process if you think about it. You're just pushing out, flushing out one fluid for another. And since you have a trailer that already has Rhomar in it the process is even easier and less intimidating.

1. There are several photos of the outflow and return portions of the reservoir. The photos posted are correct. Also you can just turn on the pump on your Alde and then look in the reservoir to see where it is flowing in to just make sure.

2. Yes that should be sufficient since you have no Century in you system. I had to first flush out the Century so I did a gravity drain then ran about 15 gallons of water through the system prior to introducing the rhomar. I also had to access all the bleeder tubes while flushing with water to get the Century out of them as the Century would just get stuck in the tubes. Probably not necessary when replacing Rhomar with Rhomar but you could do it since it is so simple just to ensure the old rhomar is removed from the bleeder tubes. On a side not I do not think using rubber stoppers is even needed if you have two people doing the procedure. With the help of my wife I did not use stoppers. I simple removed the reservoir from the wall and held the two tubes into the respective openings while she manipulated the pump and shop vac based on my directions. Can't go wrong with stoppers, and probably necessary as a solo job, but with two people not needed.

3. Yes the color will be so similar you won't be able to tell the difference. I used 3.5 gallons of Rhomar when switching from Century to Rhomar so pushing in 3-3.5 gallons you should be good to go.

4. I don't have any knowledge on the 5 year fluid except that I do not think it is approved here so not sold here. But I could be wrong?

5. I used about 15 gallons of water to flush out the Century prior to introducing the Rhomar. Probably need that much if you went from the 2 year to the 5 year product.

otr_320 · August 2023

bergger, thanks for the reply. Good to know we're heading in the right direction. We want to get a head-start on the process so we don't find ourselves procrastinating when it's due late next year. Appreciate you and Sharon_is_SAM clarifying our 320 has Rhomar (not Century). Missed that critical piece of info.

If there's enough tubing to allow us to move the reservoir in the proper position we'll certainly entertain your suggestion to insert the tubes directly into the reservoir openings.

I noticed you and a few other folks used a shop vac. I believe the vac is connected to the return side? Isn't the pump pressure on the send side alone enough to push the new fluid in and old fluid out at the same time? Curious, any chance the vac could overcome the pump and introduce air into the system??

Thanks again!

bergger · August 2023

I used the pump and suction method. With a tight seal the pump may have enough force to force out the fluid. Since I have a shop vac I opted to use it to help remove the fluid. Both the pump and vac worked in tandem. One pumping the new fluid in and the other sucking the old out. Definitely a two person job but worked well for us. I don't think the vac will introduce air into the system if done right. But I did introduce a lot of air into ours by doing a gravity drain and then allowed the reservoir to run dry as I was moving the fluid in and out. But with the newer trailers the air introduction is not a big deal. The four bleeders on our 2021 400 easily removed the air from the system, the auto bleeder and the 3 manual ones (the bed convector, behind the kitchen sink, behind the curb side dinette seat, and in the bathroom). Locate every convector in your 320 and find out how many of them have bleeder valves on them. The bleeder tube on the bedroom convector in our 400 collected the most air. It was easy to remove the air from the lines with the pump turned up to 5. Just open them up until the fluid comes out. I used a plastic cup to collect any fluid that came out. It really is a process that is not to difficult. Just don't overcomplicate or over think it. You're just removing and replacing fluid and then purging the air that gets in the lines. Just takes a couple of hours on a weekend to complete. We are due for a 2 year exchange next June but I think I'm going to do it every 3 years.

manyman297 · August 2023

@bergger I’ve yet to actually test the heat after my fluid change. How did you know you had air in your lines? Can you see it in the bleeder lines? How do you bleed the lines? Turn the Alde pump on? I’m guessing the bleeder valves unscrew allowing the fluid/air to come out?

I know I introduced a bunch of air during my fluid change but am hopeful it worked its way out but I just don’t know and with the summer heat (even at night) I can’t get the alde heat to turn on with the thermostat. Is there a way to force the heat on?

Sharon_is_SAM · August 2023

@otr_320 - the only Rhomar approved and available in the US is the variety that has the 2 year fluid change recommendation. If I recall, Alde would not warrant Aldes in TaBs made on or after 1/4/21 unless they shipped with this Rhomar.

bergger · August 2023

@manyman297 I was pretty confident I had air in the lines just from doing a gravity drain prior to pumping in the new Rhomar. Often you'll know if you do not get heat in a certain convector or convectors. But I decided to assume the air was there and bleed it out prior to having to use my heat. But yes you can also see the air in the bleeder lines but can't see any air trapped in the convectors.

Prior to changing over the glycol locate all of your bleeder valves and bleeder tubes. In my 2021 400 (very early production 2021) I have bleeder valves behind the bed, under the kitchen sink, behind the porthole window next to the entry door and the one in the bathroom under the shower controls. And of course there is the auto bleeder on the Alde unit. The valve behind the bed and under the port hole window both had bleeder tubes on them. The other two just the valve attached directly to the convector.

You do not need to turn the heat on to bleed out the air. On your Alde pump turn the dial up to 5. On the Alde control panel turn the pump to "cont." This will run the pump continuously. The "therm" setting will tie it to the thermostat and it will only run when needed. Run the pump to circulate the fluid for several minutes. This will push air in the lines to the auto bleeder and the bleeder valves and tubes. With the bleeder tubes exposed you'll see air in them. Open the valve until fluid comes out then close it. I opened all of them a few times as air would continue to collect for a bit. I opened the one on the bedroom convector the most as it appeared to collect the most air. Once your confident you have most of the air out turn the control panel back to "therm" and your pump dial back down to 2.5.

The bleeder tube in the bedroom is on the end of the convector, near the corner of the foot of the bed. I was able to feel down the gap where the heat comes out and grab it and pull it out. The one under the porthole was harder to access. I honestly cant remember if I opened it much or not. The valve under the sink required me to remove the protective wood box covering up the convector. Not hard to do. I know the newer 2022 and 2023 400s now have a tube on that convector so you do not have to remove the wood box anymore. And the one in the bathroom is simple to access, with a micro ratchet.

ScottG · August 2023

Having performed both a gravity drain and removal of all the covector hoses, I introduced a lot of air into my system. However, the vast majority of it burped out through the reservoir tank the first couple times I ran the pump on high. I assume the auto air bleeder took care of the rest. I never touched the single manual bleeder under the back bench.

This was an older (2015) 320. 400s--and maybe even the reconfigured newer 320s--may prove more of a challenge, but for me purging air after the glycol swap proved to be a non-issue. YMMV!

manyman297 · August 2023

Thanks @bergger for the thorough explanation. I'm familiar where the bleeder valves are so it shouldn't be too much of a pain to check them for air at this point. I was hoping I could test the convectors for heat prior to that to see if heat was reaching them all but it's too hot here to get the thermostat to kick the heat on. Is there a manual heat setting to force it on?

@ScottG I'm hoping my experience is the same. I ran the pump for a good 10 minutes. At first I heard a ton of air working its way through the system and the sound gradually ceased. I topped off fluid a couple of times but the reservoir level never dropped drastically.

We have a weekend trip planned so I'll bring glycol with me just in case the levels drop after towing. It sounds like some people have had air work its way out while the camper is in motion.

bergger · August 2023

I don't believe there is a way to turn the heat on without using the thermostat on the Alde Panel. I suppose you could run the AC and the heat at the same time to get it to turn on? But I also think if you run the pump on high for a while and see good movement of fluid in the reservoir that you will most likely be okay.

otr_320 · August 2023

Sharon_is_SAM said:

@otr_320 - the only Rhomar approved and available in the US is the variety that has the 2 year fluid change recommendation. If I recall, Alde would not warrant Aldes in TaBs made on or after 1/4/21 unless they shipped with this Rhomar.

Thanks, good to know. Can you recommend a good source for the Rhomar?

manyman297 · August 2023

@bergger I went and looked at the easy-to-find bleeders (kitchen sink and rear bed) and they're full of air. I can't seem to locate the passenger-side dinette bleeder. Is it under the seat? Behind the seat?

manyman297 · August 2023

Update: I found the bleeder. Not in the most intuitive area but if you remove the bottom panel of the passenger seat you can manipulate the bleeder/tube out of its vertical holder/collar and check for air. No need to remove the entire passenger side port hole window panel.

Bled the valves with the pump OFF (read somewhere else that the residual pressure in the system will push the air out...and it did. Open the valves SLOWLY if you don't want to clean up glycol spills.

I was able to get air out of all but the passenger side valve. Ran the pump on 5 for 4-5 minutes and no more air bubbles. Hoping I'm all set at this point.

Maxcamp8 · August 2023

Canned air (with propellent) will cool off the thermostat on the Alde panel and allow you to test heat circulation to the connectors. That was my strategy after glycol swap. Heating appeared even.

Did not look for a secondary air bleeder. Anyone know of location/s on a 2021 320s?

justdoit70 · August 2023

Rohmar rtu 50 fluid dealer change .It was time for my service.I was toying with the idea of doing this myself ,but could not find a supply house that had Rohmar fluid.I instead called Millers Trailers in perkasie Pa. So I got an appointment 7 days after I called.This is what I was Quoted $100.00 big ones for state inspection and $350.00 for the glycol. This is where the greatness comes in.It was a 1.5 hour drive one way dropped off at Miller tire &auto that is there service location about 3 mi. From sales lot. I met Preston the owner of Millers WOW this man is nucamp! He knows these campers in side and out. Told us places to eat and explore while we where there.So off we went my wife and grandson Karson. Got some food and went to Peace Valley park nice place to walk fish and bike. We will do a day trip here it’s that nice. Back to the service. We were called about 2.5 hours later.I have never had a State Inspection like this.So through,It was much more than breaks ,tires,lights. Preston did 2 minor repairs that he said were warranty items step and inside door glass frame. I did not even ask, he pointed this out, how fantastic. I got a gallon of Rohmar from them @$45.00 So about $500.00 for the quality of work done was very fair in my book and no long 2-3 months out wait for service to boot.
This flush vac. flush again and fill was done using the nucamp service tools. Convectors and other ALDE parts inspected for trouble, none was noted.I don’t think you will find a more dedicated sales/service dealer in the area. Try them I believe you will be pleased.I know we are.Camp on!
Thank you Millers Trailer sales & service.
Ed &Cathy
21 t@b400 solo
2016 Taco Trd Sport 4x4

bergger · August 2023

@manyman297 glad you found that last bleeder tube. Yeah it's a bit tough to find and get to that one. Sorry I did not respond earlier as we were off enjoying T@borado for the past several days.

BridgerSunset · August 2023

Just another data point, and another note of appreciation for @ScottG for documenting that changeover procedure. I was able to use it to successfully (I think) complete the initial Rhomar exchange on our 2021 400. I used 3/8" copper tubing to stab into the rubber stoppers, and it all sealed up well. A simple hand pump was sufficient and efficient. Never had to dismantle the reservoir or its surrounds to displace 4 gallons.

Thanks for all the containment tips from him & @bergger & other trailblazers - came in handy to not create a sticky mess!

pH of spent fluid was about 8.4, and the old Rhomar color looked pretty much like the new, and appeared clean. I only visually inspected the one convector under the rear dinette, and was relieved to find no bulging so far.

tombeaux · September 2023

Just wondering why there is not more love for the shop vac option of removing the fluid and then adding the new. NOTE: I coupled my Alde fluid change with checking the condition of all the fittings on my late 2017 320S (visit Mark Tunney's thorough YouTube on the subject of corrosion and fitting service here). I figured that would be much easier and cleaner with the system empty. I fashioned a suction apparatus using the @sqrpeg method discussed earlier in this thread. I sucked fluid out with my shop vac and then opened the drain on the bottom, getting another pint or so. The total was about 1.75 gallons which seems to be the consensus on what that vintage 320S holds. I used a funnel to pour it back into the reservoir for refilling. It works. At the time, I got two gallons of the Century 21 fluid via Amazon for $80. I gather the price has gone up to $100 now. The parts @sqrpeg suggested were less than $20 and I had the shop vac. Even if I didn't have the shop vac, Harbor Freight has one for $60 and the hose on that one would slip right into the clear tubing recommended for the job.

AnOldUR · September 2023

@tombeaux Rather than using the old Century fluid you could have used the Alde fluid that's recommended by nuCamp. It's now listed on Amazon for $45/gallon. Same Rhomar stuff?

https://www.amazon.com/Truma-Resistance-Components-Conditions-Eco-Friendly/dp/B0C7J6WBRP/ref=sr_1_1_sspa?crid=3JMWKM66QXETF&keywords=alde+fluid&qid=1693588443&sprefix=alde+f,aps,159&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1

Although I see there's only one in stock at this time ...

DanWeitzel · September 2023

tombeaux said:

Just wondering why there is not more love for the shop vac option of removing the fluid and then adding the new. NOTE: I coupled my Alde fluid change with checking the condition of all the fittings on my late 2017 320S (visit Mark Tunney's thorough YouTube on the subject of corrosion and fitting service here). I figured that would be much easier and cleaner with the system empty. I fashioned a suction apparatus using the @sqrpeg method discussed earlier in this thread. I sucked fluid out with my shop vac and then opened the drain on the bottom, getting another pint or so. The total was about 1.75 gallons which seems to be the consensus on what that vintage 320S holds. I used a funnel to pour it back into the reservoir for refilling. It works. At the time, I got two gallons of the Century 21 fluid via Amazon for $80. I gather the price has gone up to $100 now. The parts @sqrpeg suggested were less than $20 and I had the shop vac. Even if I didn't have the shop vac, Harbor Freight has one for $60 and the hose on that one would slip right into the clear tubing recommended for the job.

I used the shop vac method on our 2016 T@B with equally good success. Took only a couple of minutes to suck the system dry and with opening the bottom drain got about the same 1.75 gallons out. Due to hose bulging I removed all the (4) convector to clean the tube ends and all the straight thru connectors as well so I know the system was empty. Put everything back together (replaced the straight thru connector with new Alde plastic ones) and refilled the system. Took the same amount of TF-1 to refill. Ran the circu pump on #5 for about 1/2 hour & heated up the Alde to check for any leaks. All worked fine. Camping World had the TF-1 for $30 (tax included)/gallon this past spring.

BridgerSunset · September 2023

Take this for whatever it's worth regarding pushing or pulling fluid through a piping system:

I've seen situations elsewhere where a fluid-filled system is rated for a certain amount of positive pressure; however it may or may not be rated for much negative pressure (vacuum). In such a scenario, the result could be collapse of tank or piping walls, even if metal.

By no means do I know or even think that's the case with the Alde, and I suspect the design is sound enough to preclude collapse. The tank overflow is there, among other reasons, to help during normal operation.

But if the glycol piping system is essentially a closed loop (depending on how we are evacuating it during fluid changeover) then I'd be inclined to think about and be careful with how vigorously we push or pull fluid through it.

tombeaux · September 2023

@BridgerSunset Good observation, buts it my understanding that shop vacs are high volume but low pressure, and it’s not a big risk. This is out of the realm of my expertise. I can tell you that using the techniques described, I never got a great seal, so it seemed like a low to no risk proposition of damaging the system.

manyman297 · September 2023

In my situation I simply used the 12v pump off of Amazon. It took maybe 10 minutes to pump 5 gallons of fluid. To me it didn’t seem worth the effort to get my shop vac (which I use almost exclusively dry) out to save a few minutes. And I like that the 12v pump was just a slow and steady push.

tombeaux · September 2023

@manyman297 - A good point, but I wanted my system dry (actually, there is some residue, but dry enough for changing fluid) first to go through it and check for and remove corrosion.

manyman297 · September 2023

@tombeaux I didn’t realize that was the reason for the shop vac (to dry the system out). I kept seeing people use the shop vac and wondered what the point was. This makes sense now that you’ve mentioned it.

Horigan · September 2023

When using the shopvac method you're not evacuating a closed system because the other hose to the reservoir (basically the other end of the system being evacuated) is open

manyman297 · September 2023

@Horigan I read of some people using both a shop vac and a pump on both ends. This seemed odd to me since the suction and push probably isn’t equal and would cancel each other out.

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