Changing out the Alde fluid.

gregndeb

Here is an addendum to my earlier post in 2020 about changing fluid.  I added clarification and some different ways to do it.

This is an addendum to my 2020 fluid changing notes.  This is what I did when converting from the older “yellow” Century fluid to the newer Rohmer fluid.  I still went with my theory to minimize fluid waste and not create air pockets.  I did NOT flush my system with distilled water or DI water.  I preferred not to introduce any potential of adding anything that might be corrosive (including water).  Thus our system only had old fluid, maybe a small air bubble here or there and the new fluid.   

 

Expansion tank

To clarify, the fluid line GOING TO the expansion tank is on the lower right side.  The molded reservoir has a lower depression in that area.  (This is counter intuitive to me, I would think that the suction would be from the lowest possible point.  This would permit some operation, just in case one was low on fluid.)  There may be other reasons that I am not aware.  Here’s a picture.  Inlet to the reservoir is to the right.  Suction from the reservoir is center, elightly left.

 

Note I have a plumbing “test plug” as my cap, as our original cap didn’t fit very well.  We did get some splashing out of that reservoir into our closet.  The test plug has worked well enough that I haven’t been motivated to change the reservoir yet. 

 

Removing excess fluid

My previous procedure to remove the excess fluid was to put a tube down the inlet and suck the fluid out with a small pump (drill pump, or similar). 

This time, I removed the drain plug from the Alde System and only let out a slight amount of fluid.  I just drained the reservoir dry, plus maybe a little more.  (It was maybe a quart of fluid, that’s it.)  That prevented the introduction of air bubbles.  I reinserted the plug, but didn’t reinstall the hose clamp, YET!

The drain of our 2018-CS trailer is located about 10 inches ahead of the drivers-side tire.

 

I then did the earlier procedure to flush out the old and replace with new fluid.  That system has worked well for me.  If you have both rubber adapters inserted into the fittings on the bottom of the reservoir, there is no leakage.  (You don’t have to press very hard ether.)

After that was completed, I drained out the tiny amount of old fluid that was in the drain area.  I just removed and quickly reinserted the drain plug.  It was a little messy, but was done quickly.  Maybe there was ½ cup of fluid.  THEN you can reinstall the hose clamp on the drain.

 

Other trailer model thoughts:

I have used my setup on our 2018-CS (no bathroom) and an earlier 320.  We had sufficient room to use that setup.  Alde used to have a setup that they would lend (with a deposit) to users but that was prior to them being part of Truma.  Note that their setup is a little shorter overall.  The suction side only draws from the reservoir tank, which would not capture the older fluid very well.  Here is a picture from an older Alde manual.

gregndeb

Oh yeah, I put a footswitch on the pump.  That allowed me to hold the plumbing adapter in place and start things rolling.  I had one assistant that checked the color of the fluid and supplied the new fluid when needed.  

Jake_Elwood_and_us

  Just finished doing my glycol exchange.

 This instruction is for my 2021 400 with the upgraded double drain. YMMV.

  1) Pinch close the middle part of the double drain with needle nose vice grips.

  2) Hook up the glycol fill line to the port which goes to the Alde pump and start pumping.

  3) Keep an eye on the reservior to make sure it does not overfill.

  4) Allow the return line to drain into a 5 gallon bucket until 3.5 gallons have been returned.

  5) Pinch off the fill port and cap off both ports.

  6) Run the glycol pump on high (5) for 20 minutes to allow mixing and air removal.

  7) Lower pump to 2 and start heating, check reservoir level and bleed as necessary.

  Done!