Changing out the Alde fluid.

Carsoncitysmith

Strategic retreat:  Having added two gallons of distilled water and gotten back one gallon +/- of dilute glycol and not seeing a clear path to completing the replacement, and expecting a hard freeze tonight, I refilled the Reservoir with the old glycol I had removed and I am now running the Alde heater to fully circulate and hopefully mix the gallon of water that is now lost in the system someplace.  Trusting that it will not freeze and blow the whole system overnight.   I will resume this chore when I catch my breath. 

qhumberd

@Carsoncitysmith hopefully once you do this once it will get easier. It did for me.

A couple of points. Your photo of the air bleeder in a cabinet does not exist in my 2019.  The only bleeder is in the bathroom under two small Phillips screws (a little hard to get to unless you have a stubby driver). Here is a pic on the small cover removed (screws receiver areas on either end):



Now in my flush and fill I pulled the drain plug under the trailer and got about 1 gal, like you. My closet reservoir did not drain until I opened the bath bleeder above, and then the rest of the reservoir drained. At that point I removed the hoses to the reservoir as shown here and began to pump distilled water thru



This pic shows the distilled water going to the Alde on R and the first of the remaining glycol being pushed out on the L below:



It took 5 gallons of distilled water to get a true clear return from my system. Then I began to refill with new glycol. It took about 2.5 gal to start to see a color change from the distilled water back to the glycol color, and then I put another gal of fresh glycol thru to make sure, leaving a 1/2 gal to refill the reservoir and purge any remaining air from the loop. When purging you need to increase the pump or pumps to 5 and watch the reservoir and refill as it drops. On my second flush and refill it took very little extra, as I had not blown out or vacuumed the system, only drained and flushed.

I did open the bath valve after each time of running the pump on 5 to get the small amount of air which would rise to the point. Otherwise no problems either time.

NOTE: I am not sure if you have to do anything extra with the Flow pump or not. I did not on the first exchange, and then did on the second. You have to force the Flow pump on by setting the hot water setting on max. That turns on the Flow pump and I noted that the regular pump does not operate in this mode. Maybe that moves some glycol that might be trapped in the Flow unit? 

At any rate my system has worked well each time. If I were your I would flush the same way but between pump cycles after refilling I would briefly open each bleed valve you find to release any air until glycol flows. I am not sure if your additional bleeds would aid in draining, but at that stage of the process it would be worth a try as the bath bleed did help drain my reservoir and those related hoses.

Good luck after you get back to it. Just let us know what you learn and we can pass it on.

Carsoncitysmith

That procedure sounds good to me except that SCottG 's instructions are clear about taking the hoses and bleeder apart over by the Alde unit and then pressurizing some hose there to push the rest out.  

I think the pump by the Flow is meant to work while the general circulation pump is not working, to prioritize heating water over heating the convectors, when hotter water is required. 

I want to get 3 (+?) gallons of old yellow out and I seem be only be getting maybe 2 gallons out.  Maybe the 5 gallons of flush will find the missing gallon of old Yellow, but then if I don't get my five gallons of flush blackout that will mean I am leaving maybe a gallon or more of plain old water somewhere in the system, which is going to dilute the new Blue, the already diluted new Blue.  
 
Maybe I should just try that and be prepared to buy a 4th gallon of new Blue to add later?
How hard can it be?

Note: My reservoir is in an awkward place, upper front left corner of the trailer and I found it simple to detach the hoses from the bottom and to press in ¾" plugs for my pump and drain lines. 

P.

ScottG

@Carsoncitysmith, glad to see you are tackling this job with gusto, and that my DIY write-up was helpful. It's worth noting, however, that my method was based on a 2015 "320" with a much simpler glycol loop than a modern 400 with the Flow unit. I can't guarantee everything will work the same for you, but please keep plugging at it and report back on your results!

qhumberd

Carsoncitysmith said:

That procedure sounds good to me except that SCottG 's instructions are clear about taking the hoses and bleeder apart over by the Alde unit and then pressurizing some hose there to push the rest out.  

I think the pump by the Flow is meant to work while the general circulation pump is not working, to prioritize heating water over heating the convectors, when hotter water is required. 

I want to get 3 (+?) gallons of old yellow out and I seem be only be getting maybe 2 gallons out.  Maybe the 5 gallons of flush will find the missing gallon of old Yellow, but then if I don't get my five gallons of flush blackout that will mean I am leaving maybe a gallon or more of plain old water somewhere in the system, which is going to dilute the new Blue, the already diluted new Blue.  
 
Maybe I should just try that and be prepared to buy a 4th gallon of new Blue to add later?
How hard can it be?

Note: My reservoir is in an awkward place, upper front left corner of the trailer and I found it simple to detach the hoses from the bottom and to press in ¾" plugs for my pump and drain lines. 

P.

It certainly sounds like you have the right procedure going, but from what I understand you must be thorough in removing all the Century yellow fluid before adding the non compatible Rhomar blue. Some have even mentioned a cleaner before the new fluid. That would be a Truma call I suppose. 

At any rate if you can access the hoses from your reservoir then it seems you can pump as much distilled as you need to get a clear return. If you are pumping thru the loop, although it is longer than the 320, I cannot imagine that too much old fluid would be trapped. Another thing you might consider is to run the circulation pump when the system is full of distilled water to allow more time to fully dilute the loop. This of course takes more time.

BTW @ScottG and others might like know if you have noted any corrosion in the loop connectors that you have been able to inspect.

Carsoncitysmith

I found a video from Alde showing how to replace fluid,https://www.youtube.com/watch?v=2olLi_O8xXI.  
But this is replacement with like kind fluid, not the full purge and change to a different fluid. 

Their procedure is pull the drain plug, drain and replace, and then pump in new fluid discharging the old.
Their Alde pump doesn't look special in any way.

I just wrote Nucamp and was told that they will not share the instructions they give the Dealers with people who are just owners, but that I needed 4 gallons of the new stuff to complete the exchange.  I suspect that the extra gallon goes to expel the water remaining in the system when you have finished flushing out the old yellow fluid.

No, no sign of any corrosion/swelling around any pipe/hose fittings. 

P. 

qhumberd

4 gallons is what I used for my last flush and fill. I stayed with Century TF yellow as my system looked fine and I plan to replace the glycol every two years.

The pump in the video is I believe one that dealers use but it is seemingly more complex than the DIY methods in this thread.

Good luck!