Changing out the Alde fluid.

Tabaz

I happened to be at a local dealer when the new Little Guy trailer was being introduced a year or so ago. Spoke with a LG executive there for the opening as to they’re decision to forgo the Alde system. He said they went with a common forced-air unit because it could be repaired by any RV shop. Having lived with my Alde for 4 years (some tumultuous), I would never go back to a forced-air trailer. BUT - this whole discussion about needing special equipment to do basic maintenance is disconcerting. Based on past experience with my local dealer’s service department, I would never trust them to competently replace the fluid. Based on NuCamps recent decision to out-source their parts department, I doubt if they would address this issue directly. Perhaps a few owners could purchase the Alde pump and “rent” it to other owners at cost?

ScottG

I agree completely, @Tabaz. The Alde is a great system but they are relatively complicated and not very common. This makes them a good selling point up front, but a potential source of frustration over time.

That said, it's not a rocket, it just requires a little contemplation because of the multiple challenges and limited information and instructions. I've been consolidating notes from numerous sources--I think I have the pump operation figured out and have some ideas for duplicating it relatively simply and cost effectively. Of course, I won't know for sure until I test it on my own system and that won't be for a few months yet as the T@B is put up the winter.

I'll share my ideas once they are compiled and summarized. I'm trying to defragment all the available information, not just keep piling more on!  :-) 

Regardless, even with a clear plan and instructions this is going to be a task that requires at least modest DIY skills (but that would be true using Alde's "special" pump as well).

I'd still like to hear any additional thoughts or ideas members have. Post 'em here or PM me if you prefer. 

MiquelCamo

I wonder if we could "crowd source" a pump and share it between members?

I also thought an Airstream dealer might be a source for this service.   

ScottG

@MiquelCamo, I think that could be a great idea for some. Personally, I'd like to figure this out myself and just have my tools on hand for when they are needed. As I implied above, even with the pump some mechanical skills will still be required to attach and operate it properly.

A good place to start pursuing this might be the new Truma Service Center in Elkhart, IN. However, it looks like you will have to pay them a personal visit. This from their FAQ...

As a private individual, can I service or buy products from Alde?

You can both service and purchase products from Alde and Truma at the new Trumae Service Center .However, we have no online or phone sales. If you are not going to be in the vicinity of Truma Service Center, we refer you to our talented dealers who are trained and know about our products. You will find all service locations in North America here under ”Support”.

I have tried to use their search feature for North American service locations but all it returns is a map error. Maybe once the consolidation with Truma is complete things will work a little more smoothly.

I also agree that an Airstream dealer--if you have one near you--would probably be the  place to find a service department knowledgeable of Aldes.

ScottG

Or order one from the U.K. Yikes!

I think you will want this, too. Looks like it might be needed to fully drain or flush systems that already are filled with glycol.

pak

This may have been mentioned. Over on the Airstream forum there is a thread on alde heat. There are over 900 replies. I have not read the thread but we have kindred spirits there. I going to test the ph of my glycol today. The gallon of Century fluid states not to dilute. Use full strength. Happy Holidays

ScottG

Sounds good, @pak. Please test both the old fluid in your system and the new unused fluid (if you have it on hand) and report back what you find. It would also be helpful to know the age of your T@B and how much you run the Alde. New fluid is reported to have a pH of between 9 and 10.

I'll be doing some tests myself next week and we can compare notes.

Thanks!

Cbusguy

Thinking about the pump issue,  there are some self priming 12 volt micro fluid pumps 1300ml per minute on amazon for less than $20.    just need the correct tubing to link into the heating loop.   I would think the best spot would be directly after the over pressure /drain. seems simple enough 

ScottG

I've been perusing pump options as well. My current leaning is to employ the KISS principle and start with a hand transfer pump, but it seems there's quite a plethora of options to be had--manual, drill-mounted, 12V, and 120V--in a wide range of prices.

I've tried to find the specs on the Alde pumps. Whatever is ultimately used it will need to generate enough flow and pressure to transfer and push ~3 gallons through the Alde itself and the heating loop.

If you also want to be able to circulate with it to help bleed the air, even higher capacity is required. I suspect that is why the Alde tool employs two pumps.

DougH

I tested a fresh jug of the Century TF-1 or whatever it is called yellow glycol fluid yesterday.  Around 8.5-9 with a ph strip.  The protective oxide layer on aluminum is allegedly stable from 4.5 to 8.5.

ScottG

DougH said:

I tested a fresh jug of the TF-1 or whatever it is called yellow glycol fluid yesterday.  Around 8.5-9 with a ph strip.

Well, the MSDS (Material Safety Data Sheet) for the ready-to use Century TF-1 indicates a pH of 8.8, so your test seems to confirm that. Thanks for the info!

DougH

I sent an inquiry to Century to see if they have an opinion on when is low pH too low for an RV system like an Alde.  Couldn't find it in the Alde manuals.  I personally won't wait until I see 4.5.  Century got back to me quickly and said check with Alde.

pak

Hello, I'm getting back with my ph strip testing. My strips are calibrated from 4.0 to 7.0. To get an idea of the trends beyond the strip limits I tested 5% solution white vinegar which confirmed the low levels are yellow/orange in color and a baking soda/water solution @ 1heaping tsp to 1 oz tepid water. This came in at a dark blue confirming darker colors are at the base end of the scale. the new century fluid tested a very dark blue and the original fluid in my 2017 320 is very close to the new fluid. I realize the potential flaws in my test. My personal conclusion is the fluid has changed very little since it was first installed in 2017. The tab fluid in the reservoir is clear and the color is unchanged. Maybe this spring I will get some other ph strips and test again. At this point I am comfortable the fluid in my T@B is serviceable.

DougH

@pak ; Mines about the same age, and I've only checked it every year with a refractometer... and coolant percentage has been correct.  Has always been a light yellow like the Century TF-1 stuff, not clear, but maybe the initial fill differs by year or by dealership. I'll test the pH tomorrow too, and hope it's still as basic as yours shows.  Even though I winter camp, I don't always use the Alde (though not overwhelming, the aroma of the hot Alde rubber hosing is always noticeable).

tybladesmith

@DougH My inquiry to Century brought this quote "Please see the attached SDS per your request - you should always follow your system manufacturer's recommendations, we would suggest reaching out to your nearest Alde service center for flush/fill direction". Not real helpful. 
I guess we start dealing with Truma/Alde -Indiana. Doug, I like your comment about aluminum oxide Ph and stability. From the web; When the pH of the coolant drops to 7 or below, aluminum becomes a sacrificial anode and the cooling system is eaten away.

ScottG

I did the go-around with Century about a week ago. The person who replied did say "Century Transfer Fluid provides a pH between 8-10" but also directed me to Alde/nuCamp for specific recommendations regarding testing and changing. Alde has so far not responded to my inquiry. Creed from nuCamp did reply--he confirmed that pH was important but was unsure of a minimum acceptable level.

In general, what I have figured out confirms comments made by others above...

As glycols degrade they create acids (pH<7). Acids eat metals, particularly aluminum. Century TF-1 is buffered to an initial pH of ~9. This slight alkalinity prevents acid-based corrosion. As the buffers degrade pH will fall and the anti-corrosive properties are lost.

Barring any additional clear advice, I'm going with the idea that a pH of at least 8 should be maintained within the system.

Once I complete my own tests (probably next week) I'll consolidate and report all this info. In the meantime, keep it coming--as more of us that independently come to the same answers we can be confident those answers are correct! 

DougH

Based on this morning's pH test with a Lowe's $9 test kit with the six-in-one strips versus yesterday's test of the TF-1 fluid, and with my limited use of the Alde, it looks like I should be able to go 47 years before draining and refilling.  Refractometer says I'm good.  The cell phone pics may not due it justice (lighting conditions not identical, but I used the cell phone camera flashlight feature for some measure of consistency).  Brand new fluid looked like 8.5-9.0 to me.  And three year old Alde fluid looked nearly identical.  Partner and I thought, if anything, the pH and / or alkalinity had slightly increased, not decreased.  So no additional glyconic acid here.  Woo-hoo!  I added a reminder to my calendar for fall of 2063 to replace the fluid.

RCB

I think Scott has identified the crux of this issue - it is necessary to maintain a minimal ph level to protect the innards of the system. So why not just  drain what you can and top the system back up. Do this on at least an annual  basis and you will keep the ph at an acceptable level. Lots of info https://www.dynalene.com/news/2015/12/faqs-for-glycol-based-heat-transfer-fluids/

tybladesmith

@RCB your dynalene link has useful info on "Burst Point" for those wanting to add PG to gray or Black water tanks. 30% PG will protect from expansion or burst down to -18F.

ScottG

RCB said:

I think Scott has identified the crux of this issue - it is necessary to maintain a minimal ph level to protect the innards of the system. So why not just  drain what you can and top the system back up. Do this on at least an annual  basis and you will keep the ph at an acceptable level. Lots of info https://www.dynalene.com/news/2015/12/faqs-for-glycol-based-heat-transfer-fluids/

That's a good general resource, @RCB, and one I hadn't found yet. Thanks!

I found this comment about the potential for pH being too high interesting--it's also consistent with the info DougH reported above...

How do heat transfer fluids affect aluminum?

Aluminum is a great material to use in a heat transfer fluid system; however, typical corrosion inhibitors may not be good enough to protect the product. The pH of typical glycol-based heat transfer fluids is too high (> 9.0). Aluminum behaves well at a pH of 4.5 to 8.5. You can either adjust the pH of your fluid or add an aluminum corrosion inhibitor.

However, a later section also confirms that pH should stay >8, so I think we are on the right track here, despite any official confirmation from Century Chemical or Alde.

Ultimately I think your proposal to just drain what you can and top up annually would work to keep the pH acceptable, but (as noted in Autin's response to Michigan_Mike above) there are other arguments for completely flushing out and replacing all the fluid.

pak

I would expect that the aluminum parts exposed to a corrosive environment are treated e.g. alidined or anodized. I'm not all that interested in taking the time to research this. After reading this thread, checking the ph will go on a regular schedule. I consider the alde system one of the neatest things about the T@B. This forum is a terrific resource. Thank you.

tybladesmith

I drained and refilled the heating system yesterday while adding a basement loop to heat the tanks and dump valves. 

I raised the tongue all the way up and then pulled the red drain plug. The reservoir drained. I then opened the hose at the Flow Out and blew and was able to move PG to the drain. I then used regulated compressed air and got out about 2 gallons estimated -(should be very low pressure) don't ask. I would have used a bicycle pump if an adapter was near by. 

After putting the hoses back together I used a hand pump (Camco winterizing kit) to put back the 2 gallons using the low point drain and Hose clamping tool to crimp hose while installing the red plug. The tongue was lowered all the way to aid bleeding air out. Then the pump was used to add to the reservoir to get the level and keep it to 1/2" above Min. while running the Alde circulation pump at 5 setting to bleed the air out. The pump hoses can be reversed to draw down the reservoir level. Start to finish in under an hour. 




PH tested about 9.0

ScottG

Nice work @tybladesmith!

When you say you "opened the hose at the Flow Out" are you referring to where the glycol heating loop (large black hose) exits the top of the Alde? (See "convector loop out" in the photo below.)

Did you encounter any difficulty bleeding the system? Did you have to use the manual bleed valve at all, or did the auto-bleeder take care of it?

(12/24/19: Photo edited to correct labeling.)

ScottG

Also, when you used your pump to fill via the low point drain, did you have any issue with the glycol trying to just back up into the reservoir tank instead of filling the rest of the system?

tybladesmith

@ScottG, Yes the Convector Loop out. 
FYI on this pic the label "To expansion tank" should be "To Convector" 
After draining the reservoir and lowering the trailer tongue, the Alde Convector Out connection is the high point in the system but I did use a Hose pinch/clamp tool to be safer. I did not achieve 100% shutoff with the clamp tool. Maybe an added shim in between the jaws would help squeeze tighter to prevent spillage.

Because I added a new low point drain at the dump valves area, that is where I added fluid from. I was hoping the fluid rising in the system would move the air out ahead of it. I don't know how well using the standard low point drain to fill from would work because it is between the reservoir and the circulation pump which may restrict fluid flow when trying to fill the system.
I did have two spills. One when I used compressed air from the spare tire through an air blow gun. I assumed it didn't flow very much volume but because the original low point drain had a 1/4" NPT nipple in it for a hose adapter, drain flow was restricted causing overflow out the reservoir cap ( not tightened). I think a tire pump might have  provided enough air flow to move most of the fluid out. The second spill happened while adding the drained fluid back in. I also assumed that if it came out it should fit going back in, considering I had added 19 feet of hose worth of volume or .58 gallon. I was up near the tongue pumping and no one was monitoring the reservoir. The reservoir was overflowing when inspected. The reservoir is much smaller than expected. In only a few pump strokes the reservoir level goes from empty to full.
I did not encounter any difficulties bleeding the system. I did not need to open the manual bleed valve located in the passenger side storage back corner in the hose elbow. I was not aware of the auto-bleed opening. With the reservoir at full I turned the circulation pump on and turned it up to 5. You could hear the air gurgling out the reservoir. The level would drop to empty. I would shut off the pump and refill the reservoir. After maybe two or three fills of the reservoir the bleeding was completed. I reversed the winterizing pump hoses and in one or two strokes lowered the reservoir level to Min + 1/2". I ran the heat for a half hour, glycol temp was 170F. I heard no more gurgling, and the level hadn't changed. I turned the pump setting back to 2. Done easy peasy. (for an old helicopter mechanic)

Next time I would try adding PG through the Alde Convector Loop Out/ Flow Out hose with the hand pump. Keep rags handy because the reservoir will become the high point in the system. The hose clamp tool would become mandatory. 


New low point drain in the basement dump valve and tank heating project. Before insulating and reinstalling the Coroplast underbelly and building a valve box like @Tabaz has presented in the thread "Winter Use of our T@b". 

I did buy a small immersion 12VDC pump but never tried it. The hand pump is pretty efficient and more controllable for a one person job.  

ScottG

Thank you for the detailed response and additional info, @tybladesmith. Your real-world experience confirms much of what I (and others) suspect about the system but have not tested.

Thank you also for pointing out the incorrect label in my photo. I will correct and repost.

I've also wondered about the effect of pumping glycol in upstream from the circulator pump. However, that is where the Alde service pump is typically connected (on the reservoir outflow) so I assume the glycol can just force its way through the pump and into the rest of the system.

When I get to it, I'll probably try filling from the reservoir outflow on my own system--it appears to be the highest point in the system so it might reduce the risk of spillage and the introduction of air even more. There is a wrinkle, though--I have a 2015 without the little storage compartments, so getting to the reservoir fittings is relatively easy. It doesn't look like this is the case with later models where the reservoir is more deeply buried in cabinetry, so a different fill point may be needed in those cases. (Same applies to CS-S models where the reservoir is in the wall behind the toilet.) Makes me wonder how shops using the Alde service pump do it--or if they do it...

ScottG

For you engineers and master mechanics needing something to ruminate on while you digest your holiday dinners, here's a set of schematics I sketched up to show how the mysterious Alde service pump works. While I make no guarantees, I'm confident these are correct with regard to the basic operations.

tybladesmith

@ScottG I think you nailed it. After studying the Alde service pump photos I was wondering if the pumps are just fresh water pumps like the Shureflow in a T@b. FYI something to think about. 
New service Pump. 
Only for use with bottom-fill design heating systems. It looks like it uses solenoids and an actuated 3-way valve for control of fluid direction. Me just guessing!
https://www.alde.us/our-products/bottom-fill-service-pump/
This is where I got the idea to fill from my systems new low point drain. YMMV

ScottG

Interesting find, @tybladesmith. That's the first I see of that pump, and I was on that site very recently. I also notice the original 1900-811 service pump is not available there.

I unclear what constitutes a "bottom-fill design heating system"--everything I've ever seen with regard to ours says to fill from the reservoir. Regardless, bottom fill apparently worked for you so I don't know what difference it makes.

I've wondered the same about the brand of the pumps themselves, and even shopped a number of Shureflow options, including a ~140 general utility pump. Like you, I ultimately decided to that for such a small volume I'd give it a go first with a ~$15 hand pump.

I'm starting to think the only real advantage of the Alde service pump is speed and convenience, as the 3-way valve allows for rapid switching between filling, bleeding, and siphoning with a single set up. Important perhaps for a shop trying to service multiple units in a day, maybe not so much for an individual owner tackling this once every few years.

ChanW

I like the idea of the bottom fill, pushing the air 'up' and out. On ours, the hoses would need to be switched on at least one convector (haven't checked the other two), to put the low 'port' on each convector closest to the low point on the system, so the air is always 'rising' ahead of the fluid while filling.

Also, thanks for finding that hand pump, @tybladesmith. I like it better than the electric pump idea for being able to have control over how quickly it fills.

I'll still need to add a second drain port. As is, ours could never fully drain with its 3-convector & hose layout.