Another Alde convector corrosion post

crobo · October 20

Looks like this subject has been kicked around for quite some time with tons of post. Hard to read through all of them, though I'm trying. Lots of theories and no real help from Alde and Nucamp seem to be the prevailing talk. But here goes.

I bought a 2024 Tab 320 this spring from a private owner that had it a year and never used it. Got it for a good price. Was going to buy a camper next year but stumbled on to this.

I started researching things and came across the Alde 2 year glycol change. Lots of post on this also including do it yourself which I haven't researched much yet. I live a hour from Nucamp so called them about the glycol change. They do it for $600. Told them the history of the camper and asked since it hadn't been used whether in needed it this year. He told me it was ok to wait 2 years to do it.

We camped a little over a week this year, 3 different short trips. Used the hot water on all the trips and the heat for a few nights, a few weeks ago. All works great. Glycol level in the tank never moved.

I decided to look at all my convectors yesterday to find out where they were and look at the connecting hoses, all looks good.

So a few questions

Is Nucamps suggestion to wait a few more years to change the glycol a good one? Thought I might have them do it after next year. Also will research doing it myself and see if that looks feasible. Since there seems to be no real consensus on whether the glycol goes bad, or its poor clamping where the hose and convector connect, or a grounding issue, or Divine intervention that cause the corrosion problem.

2. I know I have the newer glycol, they started using in 2021 I think. Better corrosion protection supposedly. Seems they updated some things with the Alde system also. All the corrosion post seem to be older post. Anyone been using the new system for the last 4 or 5 years? Any issues yet and how often have you changed the glycol?

Seems to be an overly complicated system that some owners my not be aware they even have to change the fluid. Works great though.

qhumberd · October 20

Is Nucamps suggestion to wait a few more years to change the glycol a good one? Thought I might have them do it after next year. Also will research doing it myself and see if that looks feasible. Since there seems to be no real consensus on whether the glycol goes bad, or its poor clamping where the hose and convector connect, or a grounding issue, or Divine intervention that cause the corrosion problem.

@crobo This issue is the only one that owners have been pretty much left to figure out on their own, in my opinion. However, I have not heard that NuCamp has recommended anything other than a 2 year glycol change for old or new glycol, so I would be a little skeptical of that.

As far as the DIY change, that is not very hard for most folks. IF your reservoir is easy to get to, the change can be done in a couple of hours max. The primary expense is the glycol itself.

As for question #2, I would also be interested to hear about corrosion with the new glycol. I believe there have been some posts on this, but as you mentioned the thread is getting very long. I am sure some others may be more up to date on this.

Enjoy your new camper!

crobo · October 20

Yeah I thought going another 2 years was pushing it. Might wait another year making 3 years for the change

As far as the DIY change, that is not very hard for most folks. IF your reservoir is easy to get to, the change can be done in a couple of hours max. The primary expense is the glycol itself.

@qhumberd MY reservoir is pretty easy to get to. Do you have a link to a video or instructions on doing the glycol change? How much glycol does it take? Thanks.

qhumberd · October 21

https://tab-rv.vanillacommunity.com/discussion/comment/223527#Comment_223527

Updated glycol exchange with pump

crobo · October 21

Thanks

qhumberd · October 21

Qhumberd T@B forum procedure for 2019 T@B 400 with Alde 3020 and reservoir
in closet. Fluid flush and refill with submersible 12V pump. Completed Sept 2026
Unplug 120VAC power from Alde. Battery switch ON
Close propane valve
Set circulation pump to Continuous at Alde control panel
Turn off Alde at control panel
Remove cover from Alde reservoir. On 2019 with closet you can loosen
screws and slide it under wood panel above for access to reservoir top.
Remove top cover from bathroom Alde heater to access bleed screw
Drain glycol from drain at bottom of trailer behind wheel on driver side (red
bung). (Almost all the fluid should drain from reservoir). Drain amount will
vary but in my case was less than 1 ½ gallons).
Open bathroom bleed screw and continue to drain until you see no fluid in
reservoir, then close.
Put plug (red bung) back in outer drain below trailer under reservoir.
Lubricate reservoir hoses with small amt of silicone spray, as the connection
may be brittle
Loosen and slide clamps down on hose. Hoses should slide off with mild twist
and care
Place screw clamps on hoses, and attach elbows and clear vinyl tubing
Run flow outlet hose (on Right in 400) to submersible pump with switch. Plug
pump into 12V lighter outlet.
Run lower inlet hose (on Left in 400) to drain bucket
Fill rinsing bucket with distilled water, 4 gal, and turn on pump. Flow begins
slowly then speeds up. Color changes to clear around the 3rd gal of flush
Begin refill with fresh glycol. Watch for color change in tubing. In 400 color
change noted after 2 gallons. Use 3 gallons and save 1 gal for reservoir.
Disconnect elbows and re attach hoses to reservoir with band clamps
Fill reservoir to MAX line with glycol
Set Alde pump(s) to setting 5 at pump (including Flow pump if installed). Flow
pump will only operate when the hot water setting is on MAX. Both do not
run at the same time.
Turn on Alde and monitor reservoir. Lots of churning in reservoir and
gurgling is normal to start. Turn off Alde when reservoir drops to Min level.
It can happen fast so watch carefully!
With the Flow attached, you can activate that pump by choosing MAX on the
hot water menu. The main pump will stop and Flow pump will start, circulating
the new glycol through that loop. Let it run for a bit then turn hot water
OFF, and turn off Alde
With pump off, open bleed valve in bath. Air will sputter and the glycol will
then flow. Close valve.
Refill reservoir and turn on Alde again. Repeat until system stops dropping
the fluid level. Turn on Alde Flow pump as desired.
Turn off pump and check bath bleed valve for air prior to each reservoir
refill. Mine had increasingly small amounts of air for 3-4 times.
Refill reservoir as required to near Max line
Reset pump to Therm on Alde control panel
Reset pumps back to original speed settings. Mine was noisy and churning at
3, quiet at 2. I reset Flow pump to 2 as well. Turn off Alde
Re-install bath bleed screw cover and reservoir cover.
Plug in Alde 120VAC plug
Open propane valve. Test for heating and hot water

I noted on my browser the pdf would not load so just did a cut and past. Also the amount of glycol for the 320 is less than the 400. Just wanted to clarify.

Another Alde convector corrosion post

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