Are Alde Electric Heating Elements Replaceable?

BrianZ

I would like to know if the Alde electric heating elements are replaceable (like they are in a home hot water heater), and also what is their normal life expectancy or replacement interval?
Anybody know?

ScottG

Good question.

The Alde U.K. service manual shows the electric heating elements as separate parts, but doesn't address individually replacing them. I would not be surprised if they were considered part of the boiler body: an integrated unit that includes the flame, glycol, and HW chambers.

When I researched this previously, it appeared the boiler body was only available as a single, integrated unit (i.e., not separate parts). In addition, it was only available through "Alde Premium Service" (or some such thing) that I interpreted to be professional installation. Oh, and I only found this in Europe, and it was over $2K U.S. equivalent.

That said, it does seem like Truma/Alde U.S. might be getting their act together, so that would be a good question for them if the need arose. They may not sell you the part(s) for a DIY repair, but they might at least be able to offer service on this continent. (It's a big continent, though. For some of us going to Indiana might as well be going to Europe...)

If you get a better answer to this, please pass it along! 

BrianZ

Thanks, @ScottG.  That's pretty much what I was thinking might be the case, but not the best situation if you can't remove them to inspect for corrosion.  On a home water heater, one can also test the power terminals (with wires disconnected & circuit breaker off) on each element to check for resistance between 10-15 ohms, and a bad one would be 0-1 ohm.  I wonder if at least that could be done & how.

Tabaz

The metal cover of the Alde unit is NOT designed to be removed.  The only serviceable area is that under the black plastic portion where the fuses are located.  If you attempt to remove the metal cover, you will render the unit inoperable.

ScottG

That would certainly be consistent for the professional installation requirement for replacing the boiler body, and why none of those components are covered in the Alde service manual.

It also supports my supposition that the electric elements are not independently replaceable.

ScottG

This photo from the Alde service manual suggests you could access the electric element bolts (28), and the flame chamber locking ring (32) from the existing access panel. However, even if you could do that--and remove the end panel (27)--without breaking something, I doubt you would have the clearance to pull the flame chamber our far enough to extract the elements.

Even under the best of circumstances, this seems like a benchtop job that would require complete removal of the Alde from the trailer. @BrianZ, I'm looking forward to your report if you decide to take this on as your next project.  ;-)

 

  

BrianZ

Tabaz said:

...  If you attempt to remove the metal cover, you will render the unit inoperable.

Can you explain further?  I could render it inoperable by simply unplugging it, so not sure what you mean.  

And no, @ScottG, I don't anticipate that will be my next project.  But I may take a look at whether those heating elements can be tested without removal.

BrianZ

Ok, so I was able to check the resistance of my Alde heater elements, and found they were right around 15 Ohms each, which I assume is normal and within the normal range.  I expect that Alde could tell us what is the normal range for these elements, but at least I now have a baseline to compare with if I should ever have any reason to question whether they are functioning properly.
Here is how I got the measurements..
After removing the Alde cover at right in this photo, I unplugged the 4 plastic connectors & labeled the two at right (ac & dc power), which look the same.  Then I removed the remaining plastic tray by removing the 3 screws at the arrows..

These screws require a #10 star bit..

By lifting the plastic tray out, there is a good view of the two sets of power connectors for the two heater elements (circled) and their connections to the main circuit board (arrows)..

The gray wire is ground neutral (AC system).
Here is a closer view showing how I was able to place the probes of my multimeter inside the plastic covers to make contact with each end of the heating element for measuring its resistance..

I was careful to be gentle & not to put any stress on these connectors while making these measurements.  For the step 1 heating element (red wire), I got 14.9 Ohms..

And for the step 2 heating element (black wire), I got 15.1 Ohms..

And of course I was careful to disconnect both AC and DC power supplies before opening, so if you want to try this, be sure to do the same.  I'd be interested to hear what others measure or if you find any reference for the normal range.  Ours is a 3010 model, by the way.
References:
Alde 3010 Service Manual wiring schematic (p24) and wiring diagram (p25).
Schematic label on underside of plastic lid.
PS: No red seals were broken in this process. (Although I never found any either).
PS2:  Our home water heater elements normally read around 12.5 Ohms.
PS3:  It is not necessary to disconnect wires from the circuit board while making this measurement.  I tried that, just to be sure & my meter readings did not change at all.

Tabaz

BrianZ - In order to go into the unit any farther than what Scott shows above, the metal cover must be ripped apart.  I found no easy way to remove the other cover without significant damage.  Maybe the unit would still operate, but it would look like a hot mess.  I should have been clearer in my pervious post.

N7SHG_Ham

When measuring resistance, you need to make sure only component you are across is the one you want. Are you sure by leaving the leads connected to the elements you are doing that? I would of pulled one the wires off the element before taking a reading.

BrianZ

Thanks for the clarification, @Tabaz .
Good question, @N7SHG_Ham.  I also disconnected all three wires (red, black & gray) from the circuit board, which left my probes only across the element being measured, and I got the same readings as when connected.  In this context it makes sense that if the hot leads are switched off, leaving an open circuit in those leads, it shouldn't make any difference, since the probes would only be across the element & not measuring any resistance in the cables or other circuit. My probes were located at the element's terminals where the leads connect.  Or am I missing something?
You make a good point though - one needs to make sure they are measuring only the resistance of the component(s) of interest, and not the combined resistance of components wired in parallel (or series).  I do like your method better, since it's simpler. (If there's a more complicated way, I'll usually find it! )

N7SHG_Ham

@BrianZ, sounds like you had the elements isolated, I only mentioned it because it easy to be measuring more than the intended component inadvertently.