Sunday, December 4, 2022


Ask Dave: This will make you think twice about the Alde heating system


Calvin sent a question about his Alde heating system and some issues he was having. I did some research on it and responded to him last Friday. If you didn’t read my first response, read it here before continuing on.

Here is what came back from Calvin:

Thank you for your response. You will see from the attached I have spent hours researching the Alde heating system. Why? I personally had some “difficulties” and was unable to get solid answers from anyone (NuCamp/Truma/Alde). After getting into the forums I realized I was not alone. As you may know, it is “common wisdom” in the RV biz that only “complainers” go to the forums and so it is not representative. I disagree. NuCamp is almost a cult. Most of the comments are very positive and most of the “negative” comments are just folks trying to understand how it all works and what to do.

I’m sort of new to forums, but the problem I see with the FB NuCamp forum is you can’t sort the comments by topic and they seem to get dropped off after a period of time so there is no real history.

My quick(?) summary of the Alde heating system:

  1. All reports are that the hydronic system delivers what it promises: an efficient, comfortable, even, and quiet cabin heat along with a small amount of hot water (2.2 gal. vs. 6–10 gal.) without their add-on hot water system. As far as the basic boiler itself, I believe it takes up much less space than the conventional RV components.
  2. I do not have the numbers but I suspect even as one combined unit it is much more expensive than a conventional forced furnace and gas/electric RV water heater.
  3. Plumbing:
    • It requires considerably more intricate/expensive plumbing because all the glycol heating fluid is pumped throughout the RV to the “registers.” As I recall, the glycol is about 185 degrees, so if it leaks that could be a problem.
    • It also means there are a lot of potential leaks especially if it is not properly installed or the owner does not maintain the system. Campers also tend to bounce around. I do not think this has been a big issue as far as I can tell. Good! But I have a few I can share.
    • In very small RVs, as NuCamp builds, the boiler is located under the bed or in the case of the 620 Truck camper it is under the stove and sink and next to most of the water connections. (Do circuit boards like water?)
  1. Dealer knowledge/expertise:
  • This is not a conventional RV component and has some sophisticated electronics and unique operating characteristics.
  • Many owners seem to report their dealers are not adequately trained/experienced.
  • I do not recall my dealer mentioning anything about it. I do believe I got an Alde owner’s manual which refers to the manufacturer’s manual, which I did not get nor was told it was available online. (P.S. My RV was purchased from a very big dealer in Atlanta, GA.)
  • The directions are pretty explicit that the owner may need to add fluid and/or “bleed” the system soon after using it the first few times. No fluid is supplied, offered, nor are the Alde maintenance requirements discussed. (If so, they would most likely lose some sales.)
  1. Operating the Alde:
  • I do not know when Alde went digital, but I believe that is mostly what is being used now. As with all things digital, it will let you do most anything a space shuttle will do… when it works.
  • I do not think it is “intuitive” (at least for my age group), but the basic operation is not too bad IF you have read the manual and/or view all of the online information (some quite good). I confess… I did not read it at first because I had no idea they could make heating a 600-cu.-ft. cabin and 2+ gallons of water so complicated.
  • One unique feature is you can choose to use either 120v electric or LP gas or both.  (This seems to be a common owner question.)
  • You can operate the cabin heat w/o using the water heater (i.e., after winterizing the unit). (One of the most frequent questions.)
  • It is absolutely amazing how much digital information there is available from NuCamp, Alde/Truma and the forums about how to operate this little “mystery box” (named that by a NuCamp forum moderator/expert). ONE LITTLE PROBLEM: Most campsites in the USA have little or no internet service and many have little or no cell service (my area).  Unreasonable to expect people to remember this much information.
  • WHY? One needs to ask, why is so much information needed to operate such a basic RV component? I’ve had 20+ RVs… you set the furnace temperature and turn it on (high/low/etc.). You turn on the water heater (elec/gas) and go sit by the fire. With the Alde, you have to get out two different manuals and connect to the web???
  1. Basic Maintenance (the fine print):
    • The premixed transfer heating fluid should be replaced every two years. Why:  Because it loses some of its corrosion-preventive properties as well as its “anti-freeze” properties. If the lines corrode, they will leak. (Reports there is some 5-yr. fluid is false… Europe only, I think.)
    • While the owner can perform this maintenance, NuCamp strongly advises against it because it is complicated and critical. It is also quite expensive for a dealer to do… lots of time.
    • To do it properly, Alde says you need to buy a special pump to ensure the air is bled properly, etc.
    • Alde has changed the formula for the glycol mix a few times and says never to mix two different types. This means you have to know what kind was in the unit before you add/top off the reservoir. (Remember… they don’t provide extra.)
    • Because bacteria (they mention Legionnaires’ disease) can grow in this closed system, it needs to be “sanitized.”
    • Every 10-14 days of use (depending on the source) the water heater needs to have its “air chamber” recharged by opening a drain valve for a few seconds. They never say what happens if you fail to do this. On the same page in the Alde manual, it also says to “empty” the WH tank every 10 days to relieve some pressure. There are also conflicting videos, etc., on how to do this. “Conflicting” is a key theme here.
    • While winterizing is somewhat unique to each RV unit (responsibility of RV manufacturer per Alde), there is conflicting information about where RV antifreeze should ever be used in the Alde WH tank. (Lots of questions about this topic.)
    • Note: It appears NuCamp recently started using the Nautilus water control system and it seems to be causing a lot of issues with the winterizing process to the point the forum moderators let NuCamp know something needs to be done before there are a lot of frozen pipes, etc., and warranty claims.
  1. Performance issues:
  • The digital panel (when working) gives you some codes related to performance issues.  However, they do not tell you “why.” Some seem to be simply “false” readings that require a “reboot” of the electronics. Most of the “instructions” don’t seem to care why the default message was triggered.
  • This “reboot” and “resetting” procedure has so many versions it is mind-boggling (from the manufacturers and the owners).
  • One of the primary performance issues is related to air in the transfer fluid. Because of the different types of Alde installations, this procedure is different for every model. The common denominator is releasing the air using “relief valves.” In the NuCamp products, these valves are rarely easy to get to (the 620 is really unique), located under beds, behind panels, etc. In some cases, you have to raise and lower the opposing ends of the camper, put them on an incline, etc. (Initially NuCamp couldn’t even tell me where mine were located… I still don’t know how many I have.)
  • DC requirements: The Alde will not work without adequate 12v power. DC power is needed to light the gas heater and operate the control panel and circuit board. If the 3.15a fuse blows, the control panel is blank and nothing works. Changing this little 1/2″ fuse can be quite a chore depending on where they located the boiler unit. It is also a very unusual fuse that you don’t typically buy at a local hardware store, and it is easy to purchase the wrong replacement. (I actually got two conflicting responses from Truma as to what fuse to buy.) Alde does provide a couple of spares because they obviously know it will blow at some time. Again, lots of conflicting info about changing this fuse (not fun at 1 a.m.). (In the 620 you have to remove the range top to access the panel.) Lots of forum questions about this issue. The biggest issue for me personally was “why did it blow?” I don’t want to take the range top off very often. No good answer. If you dig hard enough, you find where NuCamp (and I think Alde) says to always turn off the Alde system before connecting/disconnecting to shore power. Who would ever think to do this? Did the dealer mention it? No. Did nuCamp customer service mention it? No. I ended up speaking with an Alde engineer (the only one who ever responded to my questions) who said that in their previous 3010 model there was a “grounding” issue that caused this. NuCamp has some instructions on how to “re-ground” certain models, but I do not believe there was a recall. I had the 3020 model which was supposed to fix this problem. A 3030 model is coming, I was told.
  • DC power continued: There were lots of questions in the forum about the Alde control panel not working when their batteries were low. How low is too low? The Alde manuals give a couple of numbers (10.5, 10.8), but these numbers are to be recorded at the Alde unit, not the battery. I don’t think this is practical for the typical owner, especially since the Alde systems are buried under beds, etc. I believe it also gives a minimum reading of 12.2v at the battery without any load. How many owners know how to do this? How many owners have a voltmeter?
  • One default code implies you are out of gas when in reality there is not enough DC power to ignite the Alde burner. (If you Google enough, you will figure it out.)
  1. RV manufacturer and Alde’s “documented” attitude:
  • It takes some practice.
  • There is a “learning curve”.
  • It is typically a “user error”.
  • NuCamp: “It is our identity” (brand).
  • If you aren’t happy—just sell it and leave us alone.
  • Truma—you are limited to six questions… sorry.

This information has been provided to others in the RV “news/review” business but surprisingly no one seems to want to upset the “apple cart,” as the old saying goes.

This is why the RV industry has gotten away with all of this for so long.

I’m sure I have left something out, but I’m sure this is more than you wanted anyway.

Honestly, assuming what I’m saying is correct, would you buy an RV with the Alde heating system? I sure wouldn’t have. My fault… I didn’t do my homework. But given the fact that there are no places to go to get real reviews, I’m not sure it would have mattered.

Thanks… Calvin

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here


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18 days ago

Yes it is more complicated, but well worth it to have quiet heat that sips propane and 12V power. You do need to invest time to learn the system, so, in that regard, it isn’t for someone who does not like doing their “homework”. The translation from Swedish has made for a sometimes altered interpretation. The Vanilla TaB forum is a good source for reliable information that retains the thread history. Like any other manufacturer, nuCamp continues to evolve and make changes. Mostly to the good.

15 days ago
Reply to  Sharon

nuCamp made it clear they do not make changes during a “production” cycle which means those subsequent units will have the unresolved issues. This does not make me feel like “family”.

Karrie Haugen
18 days ago

2018 320s. Followed directions and I get heat. Saved everything on phone for reference. Yes I would absolutely buy another Nucamp w alde. It’s quiet and provides great heat to low temps. There is a reason the fb group has such high praise and that newbies are welcomed and helped.

15 days ago
Reply to  Karrie Haugen

I am genuinely happy for those who have a good experience. I also have empathy for those who do not and there are plenty of those. In my opinion the RV and Component manufacturers should not rely on RV owners to be a substitute for ethical responsibilities.

20 days ago

I do see a lot of pros & cons for both the Alde & the standard forced air that we all pretty much use!
My first RV was a 19′ Utopia trailer that had a 12000 BTU wall furnace, just like the one we used in our house. You needed that kind of heat as that trailer had wall to wall panoramic view with jalousies windows. There is nothing better that opening them up in the summer as you get a breeze from any direction! However in the colder months, it was an ice box & you needed a 12K heater. We really miss that KISS trailer, oh ya, it had propane fixtures for lights!

Kyle Petree
20 days ago

I have some friends that had what I believe was this system in a Travato. A couple of times camping they would get an error code, a reset took care of it. Beyond that it worked for them.

However, this does raise some serious questions and while I love the concept of this type of heating system I would dig in much deeper personally before buying a rig with one.

Forums are a wonderful way to learn. But if I did everything they say we should do it would be a full time job just maintaining the RV! Everyone has to find their own happy place…..

15 days ago
Reply to  Kyle Petree

Personally I don’t like simply clearing error codes w/o knowing what caused the code. I don’t think many of us would want to do that on our car. If Alde/Truma provided instructions which said that was ok then that is a different story, but they don’t.
At 72 I’m still a little naive in thinking that RV manufacturers would have the interest of their customers in mind when they design an RV, especially one which makes a big deal out their integrity. This is a product which circulates 180+ degree fluid around your sleeping area which no one seems to consider. nuCamps admits there have been “leaks”.

20 days ago

If indeed the boiler fluid is from Century, that is the same manufacturer of the Propylene Glycol boiler fluid used in my Oasis (just like Aqua Hot) system. The President of Century Chemicals told me the PG fluid should be good for TEN years unless one sees it is materially discoloring (viewed in overflow tank.)

Maybe the specs are different for what’s used in the Alde system. Two year life sounds crazy on any quality boiler fluid.

15 days ago
Reply to  Spike

All I can tell you is that everything I’ve seen from Alde and nuCamp says 2 years. There is some conflicting info about a 5 yr life but it seems that is only for products sold in European market. The info I see says the glycol has chemicals that prevent corrosion and these break down after 2 years. The fluid in this system is heated to 180 degrees so I don’t want it leaking from corroded fittings, etc.

Bob p
20 days ago

I have spotted another fallacy, prospective buyers doing research, what a crazy idea instead of looking at the glitz.

15 days ago
Reply to  Bob p

Very true.

Bob M
20 days ago

I’ll pass on buying any RV with that system. There are enough headaches with an RV, don’t need more. Plus getting rid of the fluid would be a headache.

15 days ago
Reply to  Bob M

nuCamp and Alde do not recommend owners replacing their own fluid. Supposedly the fluid they use in the USA is non-toxic.
I think there would be a lot of “passing” if buyers were informed of the disadvantages as well as the advantages…but you don’t learn that in Marketing 101 or Business Ethics class.

20 days ago

Glad that I don’t have one. I desire to use the RV as opposed to working on it.

15 days ago
Reply to  Tom

Amen Tom.

20 days ago

I really hear the frustration from Calvin here, but as an owner of a 2019 T@B 400 model, let me share my experience since I purchased our rig used in 2020.

  1. When I knew nothing about the Alde on day 1, the prior owner showed me how to turn on the unit (I have the 3020), set the temp, and everything worked fine despite my lack of engineering knowledge.
  2. My unit came with the transfer fluid Century TF-1. I have had no leaks or loss of fluid. Guess my install was good. I have several registers around the cabin and even one under the floor of the wet bath, which is great BTW..
  3. I used the panel to figure out the hot water settings, which also worked from the start, but learning the European icons was a bit daunting. I did find you could download the manual to your smartphone and read it offline, anywhere.
  4. I have the fuses but have never needed them. I read advice to make sure the unit is OFF prior to turning power on or off. Kind of commonsense.
  5. I changed the fluid myself without any issues.
20 days ago
Reply to  Quentin

I found the Nucamp T@B forum to be extremely helpful and responsive to any questions on the Alde. Yes, there are some with issues, as with any RV component, but I like the Alde and how it works well enough to put up with reading and asking questions. So don’t let your initial frustration make you give up on a pretty innovative piece of tech.

15 days ago
Reply to  Quentin

Quentin: My initial frustration was 1. I had no idea why my fuse had blown and still do not know and when it may happen again. 2. Conflicting info about replacement fuses from Alde and nuCamp 3. The fact it was necessary to remove another component (stove top) to replace the fuse. The removal of the stove top also required disconnecting the LP gas line.
My follow-up research made me realize how many other issues there were and the conflicting resolutions. I bet if you polled the RV dealers they would not have a lot of good things to say about it except it is a good income source for maintenance and repairs.

19 days ago
Reply to  Quentin

I get Calvin’s concern regarding the Alde system, but my experience and attitude with our 2019 T@b 320 Alde is like Quentin’s. I too changed the Century fluid myself. In 2 years I’ll go thru the trouble to completely flush the system and change to whatever is recommended at that time.

Note: Airstream campers also use Alde systems.

15 days ago
Reply to  HD@1st

If I have time I’m going to start monitoring the Airstream forums. There is a possibility some of the issues are related to the installation design which Alde makes clear they are not responsible for. There are a couple of YouTube videos by a “former” Airstream owner who had a big problem with their Alde leaking Glycol. It is rather humorous the way it is presented.
I also discovered Roadtrek no longer installs Alde.

15 days ago
Reply to  Quentin


  1. I purchased my unit from a very large RV dealer in Ga. They did not demonstrate the Alde system at all. They did not mention the manual or any of the other related resources from nuCamp or Alde. (My salesman seem to have very little knowledge of the RV in general.)
  2. Like many RV mgs I think quality suffered during the pandemic.
  3. They confused me also but the manual helps w/ that. However, when you are mechanically inclined and owned 20 RVs you don’t anticipate turning on a heater requires the reading of a manual and googling.
  4. Not in agreement on the turning off power before turning off a component. I would like to do a poll on that topic. An why is it a problem sometimes and other not? An Alde engineer said it was a design issue on the 3010 and was fixed. Also there a nuCamp issue with “grounding”. Sounds like more than user “error”, “ignorance.”
  5. You are obviously a DYI person…lots of new owners are not.

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