Alde Heating System – We Lost Our Heat – Here’s how we fixed it

 Alde Heating System – We lost our heat, how we fixed it!

We woke up to a cold space the other day, which was rather strange as the Alde hydronic heating system in our 2017 Airstream classic has worked flawlessly since we moved in. The temperature has been so even throughout the space, and quiet to a point of almost complete silence, which is my favorite part.

At first I thought my temperature set point was too low, we lost power, or some other reason. It was time to find out what happened.

First Step was to raise the set point and wait for a good response. Well this turns out to be a slight downfall of the system, as it’s so quiet you can’t really tell if it’s doing anything, unlike the old traditional RV furnace and blower systems which scream I’m working!  On the Alde you can see the circulating pump icon on one of the screens, but that’s about it. Raising the set point did nothing, on to the next step.


Second Step was to turn the system on and off, figuring that a quick cycling of power might do it…waiting, waiting, wait some more, and nothing.

Third step and the most unnatural for me was to get the manual out and read it.  Unfortunately, there was nothing about troubleshooting this problem, on to the next step. We hope Alde does a revision to the manual, add a few more sections on trouble shooting and general info. That should help everyone.

Now it’s time to make some calls, 1st to Airstream, 2nd to Alde, and 3rd to my local dealer – Bay Area Airstream, who are awesome by the way!.  The general consensus was my glycol tank was too low.  I thought how could it be low, it’s a brand new trailer, surely it was filled at the factory, and made it through pre-delivery inspections?

What type of glycol do I need?

 This question I received many different answers, and nothing that pointed me to a particular brand or location to purchase more if I needed it. I won’t go into all the discussion, but I ended up with a few common items.

  • Propylene Glycol with inhibitor
  • Mixed in a 50/50 ratio with distilled water
  • GRAS “generally recognized as safe”
  • Safe for aluminum heating systems.

Above all: Do Not use the standard Ethylene Glycol we use in automotive radiators, that would be very bad for your system.

Time to check the tank level.

The Glycol tank is located in the bathroom upper cabinet, above the toilet. A service access panel is on the left side, 2 screws remove the panel and there it is. All you can really see is the screw top to the tank, and if you look really carefully between the tank and the wood panel you can barely make out a “max level” line embossed on the tank, but no min, or empty?

I made a makeshift dipstick out of a piece of plastic and marked levels on with a sharpie.

My tank was empty, on to finding the right Glycol… The only one place I could find where we are located was at a NAPA Auto, where they carry the SIERRA brand which met all the requirements. I’m sure there are other brands out there, but we needed heat and we needed it now as we were below 40 Degrees.


Filling and Bleeding the Air

I filled the tank with the 50/50 mix to my hypothetical “min level” and then turned off the circulating pump by simply turning off the system at the control panel. Caution: You must turn off the pump or you will introduce more air into the system while you think you are bleeding the air out.

Next was to bleed some of the excess air from the system.  I understand there are 2 points to bleed from, one at the towel bar and one located under the seats.  It was recommended I use the towel bar as it’s the high point in the system.

I used a towel to put around the bleed valve and cracked the valve slightly, watching some fluid releasing into the towel along with the air, then a simple tightening of the valve, and turning the system back on.

After a while I was getting heat in the front of the trailer and decided to let it be for a while. Over the next 24 hours I was able to get some heat, but not where it was right, so I filled it up to the max line, bleed the system again, and it’s been fine ever since.

Hope this will help anyone with minor blips in the Alde heating system.  It’s a fantastic system that works great.  This has just been a small learning curve like anything else.

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