Anybody Done a DIY Glycol Exchange on a 400?

manyman297

Working up the nerve to do a DIY glycol exchange on my 2021 400. Luckily I don't have to do a change from Century to Rhomar. Just swapping out old Rhomar for new. If anybody has done this on a 400, any tips? I've read the great writeup that @ScottG did but I'm wondering if the 400 has anything unique to it I should be aware of. I also had a few questions below:

• How do you know when you've pumped all of the old glycol out?
• Would a battery-operated submersible pump work just as well as a hand pump? Youtube videos I've seen show them being used so I assume yes?
• Some Youtube videos show the expansion tank completely removed to access the inlet and outlet pipes more easily. Is this recommended? 

pthomas745

This is the "Changing out the Alde glycol" thread that showed the complete breakdown of the glycol system.  It took several years to work out, and the "DIY Glycol Exchange" thread shows the results.

Many owners have done the exchange on both the 400 and the 320.  If you work backwards through the thread, you will see other owner's ideas and thoughts about the change.  There are some variations and differences in approaches, and what you are describing may be included. This link goes to the last page of the discussion, so you might page back a bit and see other owners pictures.

https://tab-rv.vanillacommunity.com/discussion/2665/changing-out-the-alde-fluid#latest

johnfconway

This particular mega thread answers questions pertinent to T@B 400...

https://tab-rv.vanillacommunity.com/discussion/13409/switching-to-new-rhomar-glycol#latest

I did use electric pump as recommended by @Dutch061. Had more than enough distilled water in one 5 gallon bucket on the "pump in" side to push out the old glycol. By the time that bucket was empty, the shop vac was running clear. Likewise on the new Rhomar, I used just a bit more than system capacity (I think 3.5 gallons?) in the pump-in bucket and verified by fluid color on shop vac side.

Unless you are unlucky enough to have or have had a 3-way frig, you should not need to remove expansion tank. I think ScottG mentions a rubber stopper with tubing inserted technique which I hope to employ next time (when it's Rhomar to Rhomar).

manyman297

Thanks @pthomas745 I've run across that thread but the sheer page count on it intimidated me. I'll go back through it again. 

@johnfconway The shop vac is what confused me in these threads. @ScottG simply used a hand pump to push new fluid through the system and the videos I've seen on YouTube show a submersible pump on the inlet side. What's the purpose of the shop vac if you already have a pump pushing fluid through from the inlet?

johnfconway

manyman297 said:

Thanks @pthomas745 I've run across that thread but the sheer page count on it intimidated me. I'll go back through it again. 

@johnfconway The shop vac is what confused me in these threads. @ScottG simply used a hand pump to push new fluid through the system and the videos I've seen on YouTube show a submersible pump on the inlet side. What's the purpose of the shop vac if you already have a pump pushing fluid through from the inlet?

I think the rationale is push and pull simultaneously. That and many already have the shop vac, so why not? Since I never got a perfect seal from tubing into shop vac wand, I think the pump was doing more than half of the work.

ScottG

I think it ultimately comes down to whatever trips your trigger. You can push the old fluid out, you can pull the old fluid out, you can dismantle everything and let gravity do the job, or you can install additional low point drains. All of the approaches seem to work.

I went with the push method in my write-up as that seemed to most closely duplicate the action of Alde's proprietary service pump. 

manyman297

@johnfconway Ahh, gotcha. That's what I was thinking but wasn't totally sure. 

@ScottG So in your experience was the hand pump sufficient enough to do the job? I'm tempted to get a battery-operated pump from Harbor Freight for $12 but I'm worried it won't have enough power to push the fluid through.

ScottG

@manyman297, I had to drain my system first  (as described in Appendix A of the DIY  document) because I needed to inspect/repair corrosion on several convector stubs. However, the hand pump was more than up to the task of refilling, and could still push fluid easily even after the system was completely filled.

That said, several owners have successfully used small electric pumps in place of the hand pump. If you peruse the exhaustive discussions you might find a few specific recommendations. Alternatively for $12 (cheaper than my hand pump...), just try the Harbor Freight pump and let us know how it works.  :-)

manyman297

@ScottG Thanks! Yeah, I'll probably try the harbor freight pump and see how that goes. The videos I've seen on YouTube show them using a 12v pump hooked to a car battery...so I'm a little skeptical about the Harbor Freight one as I think it just takes AA batteries. Might need to look at options on Amazon as well.

qhumberd

Partway down this page in the thread is my electric pump procedure. No shop vac. Getting ready to do it again and will remove the hoses but not the reservoir this time. A written step by step procedure is on my post, inspired by @Horigan who also did his 400.

BTW my Alde has worked perfectly since. No issues, no fluid loss, and hoses look good. I did add the ground to the Alde case but who know if that helps reduce corrosion risk; it was just easy and recommended.

Good luck and flush well!

https://tab-rv.vanillacommunity.com/discussion/2665/changing-out-the-alde-fluid/p17

manyman297

Thanks @qhumberd Just read through your post and downloaded the writeup you did. 

Feeling much better about the process seeing as many of you have done it already and it seems to work. Plus I don't have to flush old Century out as I'm just replacing Rhomar. NOT HAPPY about the ridiculous cost of Rhomar though. Anybody want to be a 5-year guinea pig and see if your Alde corrodes  ?

qhumberd

I am at almost 5 years with Century in our 2019 build date October 2018 and no ill effects seen. One completed flush and refill 2 years ago. Still a mystery why some people are impacted but I’m happy we have had no issues. I feel that if after this change no problems arise in 2 more years I may just stay with Century fluid for my rig.

Horigan

To know if you're having a pending issue, you need to look at the Alde radiators to see if the hoses are bulging at the connections.  The issue is more prone where there is a hose bend right to the radiator.  This is a sign of the radiator end corroding.

manyman297

When I say 5 years I was referring to Alde and Nucamp's original claim that Rhomar was good for 5 years without a refill. Right now I'm a bit over the 2 year mark...the connections I've been able to visually see look fine but I've only been able to see maybe half of them.

AnOldUR

manyman297

@AnOldUR Yeah, I was never 100% sure it was verified by Nucamp but I swear I remember seeing the original bulletin about it and it said 5 years. Could be wrong. 

I’m hoping the availability and price of this stuff improves because doing this every two years even in a DIY setting is going to get expensive (in both time and money). Love the Alde but I sometimes wonder if it’s worth the hassle.

Sharon_is_SAM

nuCamp never advocated a 5 year glycol exchange.  It stayed at 2 years like the Century glycol.  

manyman297

I guess it was Alde claiming 5 years:

https://www.facebook.com/groups/nucampowners/permalink/5250879635019296/?mibextid=W9rl1R

ScottG

In Europe, Alde recommends a different heat transfer fluid with a claimed five-year exchange cycle. However, that formulation is not approved for sale in North America, presumably because of toxicity concerns.

This has caused T@B owners quite a bit of confusion in the past. I'm not on Facebook so I can't see the specific post you refer to, but I suspect this in the case here.

As Sharon noted, the official recommendation for glycol exchange for North American Aldes has always been two years, both for the older Century fluid and the new Rohmer product.

manyman297

Mark Turney over on FB posted this:

“At the beginning of the rollout Alde and Airstream were referring their customers and dealer service shops  questions about the new product directly to Rhomar Water.

At that time Rhomar Water's RTU-50 product description had a statement about a "five year service life" attached. (The seeds of the five year servece life debacle). Note also that this fluid was "BRIGHT BLUE".. (That color will become important to the story later)

As the rollout months/years continued, things got interesting and more complicated.

The first of the complications was the takeover of Alde by a competitor company called Truma.

The second complication (for Tab trailer owners) was that is that Nucamp started their own rollout of the new fluid, but confusingly Nucamp's rollout was NOT retroactive to their fleet. Instead of letters to their custoomers, the released a "service bullitin" listing a specific "date driven" swap. Trailers after that specific build date would have RTU-50 installed, but trailers built previous to that date would NOT be called in for a swap, and in fact we're given the green light to continue using the yellow Century TF-1 fluid.

When that service bulletin hit, as expected, it sparked a lot of interest and questions about who, what, when, where, and why of the swap in the tab community.

What was this new fluid?

Why was it so expensive?

If the old fluid was bad, why not a total recall of the fleet?

Etc, etc etc. 

Then things started going sideways...lol

Alde owners, (Airstream's and Nucamp's) started doing some research...

One of the things they found was a "red herring" in Europe, that added to the five year service debacle.

The alde fluid being sold in Europe was definitely a "five year" product. It said so right on the bottle.”

So part of it sounds like a confusion over the US and European variations of the Glycol. 

It does seem crazy that a simple heat transfer fluid is only good for two years regardless of how often it is used. You would assume the heating cycles would play a part in wearing down the fluid. Folks like me who use the camper maybe less than half the year are rarely using the Alde compared to full timers or extensive travellers. I understand simplifying things down to a time period makes things easy but I wish they’d come up with a method of testing the Glycol which would be more definitive. But I’m no chemical engineer so this may not even be possible.

qhumberd

qhumberd said:

Partway down this page in the thread is my electric pump procedure. No shop vac. Getting ready to do it again and will remove the hoses but not the reservoir this time. A written step by step procedure is on my post, inspired by @Horigan who also did his 400.

BTW my Alde has worked perfectly since. No issues, no fluid loss, and hoses look good. I did add the ground to the Alde case but who know if that helps reduce corrosion risk; it was just easy and recommended.

Good luck and flush well!

https://tab-rv.vanillacommunity.com/discussion/2665/changing-out-the-alde-fluid/p17

UPDATE Oct 2024. 

I just repeated my flush and refill procedure on my 2019 with Century (yellow green) transfer fluid. This was the second flush since the Oct 2018 build date and was very easy and the little pump worked well. Only modification this time was I only used distilled water for the flush and only did 4 gallons at which point the return was basically clear.

I then pumped in the new Century fluid and found that at about 2 1/2 gal the return changed color. I used a full 3 gal and called it good. This left about 1/2 gal to fill the reservoir. I set the main circulator pump to 5 and all the air seemed to come out in a couple minutes with only a slight drop in the reservoir. Total amount for the flush and refill was 4 gal of Century fluid.

Unsure of how the glycol flows into the Alde Flow unit I then turned the Flow pump to 5 and was able to force it on by setting the hot water setting to full on the menu. This turned off the main circulation pump and I think mixed the glycol from that loop as well.

Turned it all off and reset both pumps and it heated up with no issues both electric and propane. Was about a year over on this one but the fluid looked good and I could not see any bulges in the areas I inspected of around the boiler. Fingers crossed I am not getting corrosion as the repair looks like a major construction project.