Changing out the Alde fluid.

ScottG

db_cooper said:

@ScottG
Did you investigate the bulges at the convectors that you had noticed previously when you did your complete flush?
...

@db_cooper, yes. I wrote about that half of the project here. 

Sorry to hear you have also found bulges, but thanks for checking and weighing in.

db_cooper

@ScottG
Thanks, i somehow missed that page.  Do you think I can remove the two hoses at the rear radiator that are closest to the expansion tank without making too big of a mess, if all I do is drain the expansion tank?  That's the only bad spots I can find, and I'd like to remove the deposits if possible.   I won't be using the Alde much except for hot water until fall now,  but I'd feel better if I knew I'd cleaned them up.

ScottG

@db_cooper, I think you will get a good puddle if you disconnect that hose without draining the convector loop. At the very least, whatever is in the affected hose and convector will be coming out.

I would suggest draining the entire convector loop at the low point by removing the short section of hose between the upper and lower passenger side convectors. You'll need to first take the plywood divider out of the cabinet, and getting a suitable drain pan in there will be a challenge, but at that point you should be able to disassemble things with limited spillage.

An alternative would be to drain the boiler, disconnect the outlet hose, and blow the fluid back up into the reservoir and out the drain. This is what I described in my post above about how I drained my system.

I realize this is all more work that you were planning, but if you read the post I linked to above, you'll note that I found some degree of crystallization (and corrosion) at all the aluminum fittings--even those that had not yet formed an obvious bulge. There were also crystals in the hoses that were best removed by a thorough rinse in a sink. 

If you are intent on cleaning things up--and I make no guarantee that will stem the corrosion--you might consider inspecting all of those fittings.  :-/

db_cooper

I was afraid you'd say that!      I think I'll let the fresh gallon I put in today work through the summer, then I may tackle it in the fall, and disconnect all the fittings and clean.  While I still think the Alde is the best system for my type of use,  I wish the install and components were a bit better thought out.  A single well placed low point drain, and no dissimilar metals in the loop would be my first suggestions.   I'd like they system to last, but even with the yearly partial drains, it doesn't appear that's enough.

Denny16

The only dissimilar metal in the glycol convection loop is a short single stainless steel pipe in the door jam and the water heating tank.  That said, stainless and aluminum do not react to each other enough to cause a corrosion issue as which.  We used stainless rivets and screws in aluminum masts, subjected to salt water, worst case situation for dissimilar metal corrosion.
cheers

db_cooper

Interesting @Denny16, I've been good at putting a gallon a year since 2016 into the system and still have a little corrosion (assuming, since I haven't opened up yet).  I do run the Alde low during Dec-Feb, but figured that was better than sitting idle. If it's not galvanic in nature, what could be the cause? 

PH tests good, just trying to figure out what I need to do to make it last longer than the tires. 😜

Denny16

That is the mystery every one is trying to figure out.  We did the momplete fluid change at year 2.5, and everything looked good, no issues found.  I think one possibility is contamination in the system from something, causing the crystalline white stuff to participate out between the hoses and aluminum connectors.  It seems to be building up, especially on trailers that did not do a regular glycol change out.  Changing out one gallon at a time for a 3+ gallon system, is a partial change of fluid at best, leaving more of the old glycol in the system, than you are adding new with.
cheers

ReenieG

This convo has my head spinning. I am still stumped as to what and how to do with the glycol!! Ugh! Is there anyone in this comment thread living in Phoenix willing to lend a solo camper a hand? I've already inquired with the local dealers and none of them know what they're doing. Suggestions? Help and advice anyone? TIA

Denny16

I assume Tom’s Camperland is the clueless local dealer.  You might try giving Little Guy Trailers in San Diego a call, to see if they can schedule a fluid change for you.  If so, it’s a short road trip and a nice weekend camping destination.  . 

Good luck,
cheers

Sharon_is_SAM

@ReenieG - maybe check with the local Air Stream dealers since they seem to have a handle on the glycol exchange.  

ScottG

@ReenieG, the unfortunate quandary you are in is a large part what prompted this head-spinning discussion now dating back years.

I think the DIY options are as simple as they are going to get. If those aren't an option for you, I agree with Denny16 and Sharon's suggestions.

As a final alternative, if you have a trusted mechanic or handyman that you are willing to pay for their time, they could probably peruse this discussion and fashion the simple tools needed to make the exchange. That's essentially what @MadCityJack did and posted about back on page 11.

Good luck!

Tampakayaker

The you tube video from England changing out the fluid seems to be the easiest, if your reservoir is in a decent location.  

ScottG

This has been discussed previously, but it might be worth reiterating here for those contemplating how to fully drain their system.

The connector between the air-bleeder and the hose running to the first convector is very accessible and easy to disconnect (see image #1 below). If you blow air through this hose (with lungs, a pump, or maybe a shop-vac blower) you will eventually force the glycol trapped in the convector loop up into the reservoir. From there it will drain out the other side of the reservoir and--assuming you have left it open--out the low point drain (see image #2 below).

I collected an additional five pints using this crude method. More telling, when I did eventually pull the hoses off the lowest convectors very little additional fluid drained out. 

There is, of course, more than one way to skin a cat. Others approaches also work just fine, but this involves no modification, very little disassembly, few contortions, no rigged-up connections other than to get air pumped into the hose, and carries little risk of leakage. Frankly I was skeptical it would work, but once I tried it was amazed at how stupidly easy it was. YMMV.   



 

pak

I just recieved my transfer pump recommended by Scott. I believe I now have the necessary tools to remove/replace the fluid. I will get new fluid on my next trip to Spokane. I think after I do this once, changing the fluid will lose both it's mystery and complexity. I now will have to be through and patient to avoid a mess. I wish the issues cause could be pinned down, as my information from Century indicates if the ph is 8 to 10 the corrosion inhibitors are still effective. Evidence presented here indicates the contrary. Additionally, the switch to another glycol for newer models makes one wonder exactly why. A little information from Alde and nuCamp on this matter certainly would be helpfull. Rant over.

XenanMe

Big shout out to @ScottG for the DIY Alde glycol replacement pump idea, instructions, parts list and diagrams.  I was able to craft my very own solution similar to the one designed by @ScottG.  An absolute life saver for me since I am up in Canada, past the 2 year glycol replacement period and nowhere near an authorized Alde service centre. Today, I successfully replaced the glycol in my 2018 Tab 400.  Not counting the sourcing and assembly of the hand pump device, the entire process of draining, flushing with distilled water and replacing with new glycol took just under two hours.  It was very straightforward and - dare I say it - easy.   I was able to source the necessary parts at good ‘ole Canadian Tire (except the Century fluid which came via Amazon at an exorbitant cost).  Thank you so much to everyone on this forum for taking the time to research, experiment and document ideas and solutions.

db_cooper

@ScottG, thanks for that diagram. That's right past the check valve, correct?  I was afraid a lot of fluid would come down from the back radiator, but that looks manageable.  

ScottG

@XenanMe, thank you for the kind words. I'm glad you were able to get this job done yourself with a minimum of fuss--that was the objective right from the start!

Credit really belongs to everyone who has followed and contributed to this discussion since it began. All I did was gather and consolidate the ideas, inventions, and experiences of others.

With that in mind...  I see you have a 400, which I assume is laid out a bit differently than the 320, but still has the issue of glycol remaining trapped in the convector loops. How did you approach the draining? Did you just drain what you could from the supplied low-point drain, or did you take extra steps to blow out, vacuum, or otherwise drain the residual fluid?  

ScottG

@db_cooper, you are correct--that junction is right downstream from the check valve, which is part of the auto air bleeder assembly.

In my case, I had already remove the air-bleeder assembly form the top of the Alde (also relatively easy) to facilitate draining. It's possible that blowing air at that location (upstream from the check valve) could also work, but since I was taking everything apart anyway I didn't try this. By working at the downstream connector there was no risk of interference from--or damage to--the air bleeder or check valve.

Note that on some models, the check valve may be incorporated into the aluminum connector shown in my photo. In those cases, you may need to remove the fitting and blow directly onto the hose.

Spillage from the rear convectors wasn't a big problem. In fact, you can see how much ended up in my drip pan in the back of the photo. I was careful to keep the end of the hose high after removing it.

ScottG

@pak, I completely agree about the loss of mystery and complexity. As you said, just plan well, proceed slowly, and take care to contain any potential drips or spills.

I also agree with regard to the fluid issue. While information has been limited, nuCamp's abrupt switch to the new fluid (which Airstream initiated a year ago) suggests something is clearly up with Aldes using the Century glycol. However, it is yet unclear whether that something is related to the problem discovered here by @fstop32, or if there is another issue brewing.

I guess for now we have to trust that Alde and nuCamp are doing their homework and will eventually provide more info and, if warranted, a fair solution. 

ScottG

ChanW said:

Great @ScottG, you finally got a round tooit! Nice and simple.

I like @tybladesmith's suggestion...

Replace the existing drain tee-hose fitting with the double tee, pinch in the middle, and push out the old glycol with the new, with a distilled-water flush in between.

My reservoir has a cap with a rubber seal in the cap, so with the vent hose outlet plugged, the reservoir becomes a sealed chamber with glycol and an air cushion in it....

I could do all the pumping and draining from outside the Tab...

Anyone see something I'm missing?

(do we have a direct source for Alde parts yet, or am I going to have to go through my dealer to order - the double tee Bottom Fill & Drain fitting - Alde part# 1900 876)

tybladesmith said:

@ScottG,  Alde bottom fill dual drain hose for bottom fill systems. ? Add this inline at a low point, clamp in-between and then drain/flush with distilled water before refilling with fresh glycol. Maybe even replacing the existing drain with a dual drain and fill under slight pressure to auto purge the air into the reservoir after the isolation clamp is removed using the onboard circulation pump. What do you think? 

FWIW, I just rediscovered this diagram I had made when I was pondering the installation of a filling tee. I'm not sure I ever posted it, but it is relevant here because it is the same basic idea as what is being proposed by @tybladesmith and @ChanW. For those following, it gives a visual sense of how the glycol would flow using this setup.

 

db_cooper

@ScottG
I'm going to give this a try, and will report back how it goes.  I'll disconnect the hose at the end of the check valve, and I'm hoping the blow out plug  I use for winterizing will  fit in the hose opening,  it might take a bit of taping things together.  Then I'll use an air compressor to blow the fluid back up into the expansion tank to drain out the driver side.

I will still be adding a passenger side drain to facilitate easier changes.  Taking everything out of the trailer to protect it from spillage is a pain.  I have an inquiry through a dealer to Nucamp to see about getting the same rubber drain they use.

Last question (I swear!),  is there any reason I can't refill from the expansion tank, and use the circulation pump?  Since I'll be sticking with Century fluid I don't care about getting every last ounce out.  I don't need to pump it back in do I?

Denny16

The Alde is a low pressure system, so be sure to keep yiur compressor to around 10-20 psi max. You only need s pressure to get everyone flowing out the drain.

Cheers

db_cooper

@Denny16 , yep, I was gonna start slow and taper off.  Just like I do when hiking.

XenanMe

@ScottG I didn’t vacuum or blow out the system.  I relied on the distilled water to push out the old glycol. I drained from the existing low point exterior bung plug.  Then closed that drain and pumped in the distilled water using the hand pump method and allowing the old glycol to exit the system.  I used 4 gallons of distilled water.  Not enough to run clear but it was very pale yellow.  I had planned to run the circulation pump with the distilled water in the system but in my enthusiasm I forgot that step and proceeded to drain the distilled water from the low point.  Then I pumped the new glycol into the system with the hand pump until the water was out.  Checked the colour and the PH level of the glycol in the overflow tank to make sure it was not diluted.  Ran the circulating pump for 30 minutes or so to get the air out and added more glycol to the reservoir.  I also opened the bleeder valve in the bathroom to release any trapped air.  Checked the PH again after circulating just to be safe.  All was good and it working as expected.  It sure would be nice if Nucamp started installing the Fill and Drain tee. There is something similar to that tee on on the low point of my home solar hot water heating system and it makes changing the glycol on that system simple.  This hand pump method is a bit more challenging but at least it is a viable option.

ScottG

Sounds good, @db_cooper. I'm thinking your blow-out plug and maybe a little tape will make an excellent connector for this purpose.

One additional bit of advice for when you try this...  Keep the cap on the reservoir tank! Even a good puff from my lungs was enough to cause quite tempest as the the fluid was forced out of the glycol loop. It can easily splash out and create a bit of a mess on your walls if you have forgotten to replace the cap.  ;-)

And yes, you should be able to refill the system by just pouring new glycol into the reservoir and running the pump. I suggest keeping the pump speed low as you do this to avoid sucking the tank dray and drawing more air into the system. Once you get the whole thing refilled, you can top off the reservoir and speed up the pump to burp out any remaining air bubbles.

ScottG

Got it--thanks, @XenanMe. With the adapters, I think using new fluid to push out old is probably the simplest solution. The only reason I fully drained/blew out mine first is that I wanted to disconnect and inspect all the aluminum fittings. Either way it gets the job done!

db_cooper

@ScottG, I think you found the best way to drain the system without putting in a second drain. That was easy enough and I had no drips at any convectors when I removed the hoses. Didn't spill a drop inside, I would be comfortable doing this without emptying the camper contents, but did to be on the safe side, plus I knew I was taking all the convectors apart.

I'll post pictures of the corrosion in the corrosion thread. All hoses had some at the convectors, but the aluminum looks good, no holes or deep pitting, but worse than ScottGs.

Bayliss

Excellent advice, @ScottG!!

It's the little things (and missteps) that can ruin your whole day.  We've all "been there, done that," and learned the hard way, so these tidbits are always helpful.  Thank you.

ScottG

MOD NOTE: The discussion of the new glycol and circumstances surrounding the recommended change were generating a lot of comments, so I've moved it here.

Let's reserve this already lengthy thread to discussion of the mechanics of actually changing the glycol!

ScottG

@db_cooper, I'm glad that worked for you, and thanks for following up. It's always nice to have more than one example, just in case my own personal experience was a one-time stroke of dumb luck!  :-)