Better understanding the Alde System

Calvin

To better understand my Alde system I've spent many hours researching this major component.  I don't have all the answers but I am sharing what I have learned thus far.  Any suggestions are appreciated.

Denny16

Nice job, this should make trouble shooting the Alde easier for TaB owners.
 Cheers 

CCC

Thanks, any difference you know of in the newer 2022 model?

Denny16

No, the 2018-2023 TaBs all use the Alde 3020, with the TaB400s from 2019 on, having the Alde Flo auxiliary water heater.
 Cheers 

Dame_plume

Thank you @Calvin!  Such a great document for all, and a must for us, newbies.

AnOldUR

Trying to understand the Alde, but still not sure. From the attached picture it looks like the blue area is filled with water for our hot tap water? The next area moving inward with the "2kW Electric Element" filled with glycol? The next area, labeled "1kW Electric Element", is what I'm most curious about. It appears to be free from fluids, where the flame for gas heat would be. What doesn't seem right is the heating element in there. I had always thought that electric elements had to be submersed or they would burn out. Also having flame contacting the electric element doesn't seem right, but all this could very well be how the system works. Can anyone clarify this for me?

Yoshi_TAB

Hi, It's hard to see, but there is a shell between the hot water (blue) and the tube that holds the 2K electric element.  There is no direct contact between water and any element.  Only the alde transfer fluid is in contact with the electric heating elements (both the 2K and 1K).   The transfer fluid heats the water.  The alde transfer fluid flows in the pipes labeled 22 mm central heating.  The burner works like a home gas water heater.  The flame is behind the burner.  Sort of like a pan on a stove.  Hope that helps.. 

AnOldUR

@Yoshi_TAB I thought that there was glycol in the chamber with the 2kW element, but I'm not seeing how the chamber with the 1kW element would have glycol in it also. It looks like the 1kW element is in the same chamber as the gas fired heating. Is there another liner between the 1kW element and the burner?

Yoshi_TAB

Hi,  I enlarged the photo that may help.  I am not an alde expert, just going on what the photo indicates.  Others may help to clarify.  The picture depicts  transfer fluid in both the 2kW chamber and the 1kW.  For the 1kW  and gas burner, you can see the fluid coming in near the bottom.  It exits out by the 2 kW element.  The picture depicts a cut away, but they must be open to each other for the transfer fluid to be in contact with all 3.  I'l poke around and see if I can find an actual alde heat exchanger cut open.

ScottG

Here's a cross-section schematic of the boiler core that might help:

Also, FWIW, North American Aldes have two identical 950W electric elements. The 1kW/2kW thing applies to European units where the availability of 240V AC allows for a bit more flexibility.

AnOldUR

@ScottG That looks to be the way I had thought. Still questioning the location of the two 950W electric elements. Are they both in the glycol or is one in the glycol and the other in the propane flame chamber? From the cross section picture that I posted, it looks like one is in a chamber separate from the glycol.

Denny16

I knew the North America units didn’t have two different size heating elements (1K & 2K), but always wondered what size they actually were.  So in 1KW mode, one 950-watt element is turned on, and both elements are on in 2K mode, which is actually 1900-watts.  This confirms that one or both heating elements are selected by the control panel.  Thanks Scott.
 Cheers 

ScottG

AnOldUR said:

@ScottG That looks to be the way I had thought. Still questioning the location of the two 950W electric elements. Are they both in the glycol or is one in the glycol and the other in the propane flame chamber? From the cross section picture that I posted, it looks like one is in a chamber separate from the glycol.

They are both in the glycol, as shown in my schematic. It's a little hard to envision in the perspective cutaway provided by Alde.

ScottG

Denny16 said:

I knew the North America units didn’t have two different size heating elements (1K & 2K), but always wondered what size they actually were.  So in 1KW mode, one 950-watt element is turned on, and both elements are on in 2K mode, which is actually 1900-watts.  This confirms that one or both heating elements are selected by the control panel.  Thanks Scott.
 Cheers 

Yes, I think that is how it works. I don't have the digital control panel in my 2015, so I can't confirm for certain, but what you describe makes the most sense.

On the older analog panel, you can select either element individually, or both together.

AnOldUR

ScottG said:

... It's a little hard to envision in the perspective cutaway provided by Alde ...

Ahhh! Now I see it. Thanks.

Denny16

Grand, if the heating element is not in the glycol part of the boiler it would not work, the glycol has to be heated, to get heat to the water and heat out of rye convectors in the cabin.
 Cheers 

Yoshi_TAB

Hi,  This also now has my curiosity, I've been looking for a x-section of the boiler (an actual picture).  This is all I could find from this website:  Alde Heating (mycaravan.org.uk)  It doesn't exactly show the entire thing.  It's hard to see if the second set of heating elements are there or just not included.   tks to others for your input.  

kevenv

When I watched the NuCamp walkthrough video for the 2022 Tab 400 (at 19:45) they explained the 1kW is for 110 circuit at home and the 2 kW is for a 30amp service at the campground.

https://www.youtube.com/watch?v=Zmi0b05KlBs

Denny16

Yes this is correct, the highest setting you can use on a 15-amp (home circuit) is 1KW position, which turns on one 950-watt element.  The 2KW setting turns on both (see above) and requires a minimum of 20 amp service to use the 1900 watt load of both heating elements.
 Cheers 

pthomas745

From the Alde FAQ: Each electrical element uses 7.9 amps.  So, the 2kw setting would use 15.8 amps, hence the need for at least a 20 amp circuit.

There are two mechanisms in the Alde Compact boilers that draw >0.1 A current from the vehicle 12-volt battery. The exhaust fan venting waste gases (≈0.4 A), and the heating fluid being pumped around the circuit (≈0.2 A). So normal draw from the vehicle battery is between ≈0.2–0.6 A, including the control panel. Max draw is 1.9 A for approximately three seconds at system start-up.

Max draw from 120 V mains is ≈7,9 A on 1 (1 kW) or ≈15,8 A on 2 (2,1 kW)

jkjenn

Another note: water pouring out under the trailer is from the pressure relief valve and most of the time it is a brand new owner not using a water pressure regulator. That valve can be bad, but it is not a common problem. Usually the water pressure regulator goes bad, first.

Brian_Waz

How would one know which glycol they have in their system? In your document, you mention a newer style that has a five year live instead of two. Is there a way to identify the new one?

AnOldUR

@Brian_Waz
The five year as opposed to two year confusion refers to glycol used in Europe. It is poisonous and not legal in the US. Both the Rhomar and Century fluids used in this country have the same two year exchange period. Rather than going by the model year of your T@B, the best way to know for sure what's in your system is to look in the expansion tank for the color.

Rhomar on left, Century on right ...
(They have not been forthcoming with details, but the Rhomar is claimed to be more corrosion resistant.)

pthomas745

@Brian_Waz the first thing to note is the year of your camper.  Below is the NuCamp "press release" about the change from the Century to the Rhomar.  So, start here with your "build date".  You can find the build date on the gray sticker on the driver's side of the tongue, listed as a Month/Year.

https://nucamprv.freshdesk.com/support/solutions/articles/44002156353-2021-glycol-change

Brian_Waz

Thanks for that info

Brian_Waz

pthomas745

@Brian_Waz that "appears" to be the Century glycol, and nicely topped up, too.  Did you find the "build date" of your trailer?

Sneakle

Calvin said:

To better understand my Alde system I've spent many hours researching this major component.  I don't have all the answers but I am sharing what I have learned thus far.  Any suggestions are appreciated.

Good job Cavin and thank you. Alde is a complicated system for those that are not inclined to become engineers to manage it, and any aids to understanding it like you have made are appreciated. 

Brian_Waz

@pthomas745 its a September 2020 build date on my iD plate.

pthomas745

So, yes, a couple of months before the changeover to the Rhomar (blue) glycol type.