Alde Glycol 2-year Drain/Fill

manyman297

Since the forum is swarming with Alde questions I thought I’d add to the party. 

Next spring I need to do a drain/fill of my Rhomar glycol. I realize the switch from Century to Rhomar requires a complete flushing of the system but what’s required for the 2-year glycol maintenance replacement? Can I simply drain the old glycol and fill the system with new glycol? I saw the DIY instructions on here to build a pump. Anybody who has done this have any insight?

ScottG

On the 320, simply draining the glycol via gravity will not remove all the glycol from the system. Because of the routing of the hoses, there are places where the glycol remains trapped and needs to be forced out under pressure. I'm not absolutely certain about the 400--or about the newest models--but I suspect the same applies.

Many owners have successfully tackled glycol replacement themselves and posted about their methods and experiences in this 27-page discussion (among others). You might also find this DIY guide helpful. Although it is based on an older 320, the basic principles are the same. There are many variations in the ways owners have approached this, but most involve some method of evacuating all the old fluid before refilling with new.

manyman297

Thanks! Yeah, I ran across an article for the 400 I believe...I have it saved somewhere. The hardest part looked like making the pump. Actually removing and replacing the glycol looked like the easy part. 

Horigan

If your 400 has the closet next to the bathroom, there's easy access to the reservoir and hoses and you can use a shop vac to pull all the remaining fluid that doesn't drain out.  One hose to the reservoir will drain, the other won't and that's the one you apply the shop vac to.  

If you have the larger frig in that location, then you need to go with the pump method.

Aubrey

I have a 2018 400 with the closet and bathroom, reservoir easy to get to but having trouble finding a good description of the draining process. We have had the trailer for 2 years of very light use, almost never with heat or hot water, and haven't seen the fluid level move at all, but i would like to plan ahead. 

Aubrey

Also the jug of Century fluid we received with the trailer has been with us for that 2 years unopened. I hope its usable as well. 

bergger

I completed the drain/flush/refill, with Rhomar, this year.  In a couple of years when I replace the Rhomar with new Rhomar I will follow my same procedure but of course skip the distilled water flush of Century. I will do a gravity drain first, then use my same method of the shop vac and 12v diesel pump I bought to introduce the new Rhomar and suck out the old.  I will also go around to all 4 of our bleeder valves, like I did during the initial switch over, and open them up to purge any old glycol in the bleeder lines.  Two bleeders are mounted directly to the convectors and two have longer 12-16" extension hoses.  The longer hoses are the ones I really like to open as old glycol can get stuck in them when pushing in the new.  Should be faster and easier than what I did this year.  Which all in all was pretty easy anyway.  

Denny16

@Aubrey, the unopened Century TF is fine, it has a two year life inside the Alde, where it is in contact with the aluminum and stainless steel parts of the system.

The Alde circulation in the TaB400 has two high spots, one where it goes into the washroom wall heater unit, then back down and back up to the reservoir, which prevents the fluid forward of the reservoir from draining out the rear low point drain.  The convectors behind the galley are also up off the floor, then down to the floor under the door sill, back up to front convectors, then back down again to washroom, and traps the fluid between the galley, front and washroom.  A second and third low point drains between washroom and front and by the low point under the door to allow the front bit to gravity drain, but alas is only one in the rear, so a pump is needed to get all the glycol or flush water out.
 Cheers 

Horigan

@Aubrey
The method that's worked for me with our 400 configuration is the following:

Ensure the Alde is off.  Drain and capture glycol from Alde drain outside trailer below Alde compartment (red plug).  You'll drain about a gallon.  Close drain.

At the reservoir, one hose will have drained, the other won't because of a check valve.  Use a turkey baster to suck out the small amount of glycol in the reservoir.  Remove the hose that's full of fluid and carefully drain it into a bucket in the closet, then tape a shop vac hose to this hose.  Shop vac should have a 3 gallon capacity.  Turn on the shop vac and remove remaining fluid.

Reinstall hose to reservoir and fill system with new fluid to the reservoir full mark.  Set Alde pump(s) to level 5.  Briefly turn on Alde and turn off when the reservoir gets depleted.  Repeat multiple times until the reservoir level stabilizes.

Below bathroom shower head, remove the cover for the Alde heat exchanger and open the bleeder valve.  Close when pure fluid dribbles out.  Turn on Alde and crack bleeder until pure fluid comes out.  

Turn off Alde, replace bleeder cover, and reset Alde pump(s) to 2.5.  Monitor fluid level frequently on initial uses.  This process took 2.5 to 3 gallons of total fluid, if I recall correctly.

This method works for just replacing the current fluid with the same fluid.  If you're changing fluid (Century to Rhomar), then you need to do a drain and fill, per above, with distilled water, twice, before adding the new Rhomar fluid.

manyman297

Horigan said:

@Aubrey
The method that's worked for me with our 400 configuration is the following:

Ensure the Alde is off.  Drain and capture glycol from Alde drain outside trailer below Alde compartment (red plug).  You'll drain about a gallon.  Close drain.

At the reservoir, one hose will have drained, the other won't because of a check valve.  Use a turkey baster to suck out the small amount of glycol in the reservoir.  Remove the hose that's full of fluid and carefully drain it into a bucket in the closet, then tape a shop vac hose to this hose.  Shop vac should have a 3 gallon capacity.  Turn on the shop vac and remove remaining fluid.

Reinstall hose to reservoir and fill system with new fluid to the reservoir full mark.  Set Alde pump(s) to level 5.  Briefly turn on Alde and turn off when the reservoir gets depleted.  Repeat multiple times until the reservoir level stabilizes.

Below bathroom shower head, remove the cover for the Alde heat exchanger and open the bleeder valve.  Close when pure fluid dribbles out.  Turn on Alde and crack bleeder until pure fluid comes out.  

Turn off Alde, replace bleeder cover, and reset Alde pump(s) to 2.5.  Monitor fluid level frequently on initial uses.  This process took 2.5 to 3 gallons of total fluid, if I recall correctly.

This method works for just replacing the current fluid with the same fluid.  If you're changing fluid (Century to Rhomar), then you need to do a drain and fill, per above, with distilled water, twice, before adding the new Rhomar fluid.

Interesting. So there’s no need for the DIY pump?

ScottG

manyman297 said:

Interesting. So there’s no need for the DIY pump?

@manyman297, while a pump can facilitate forcing new fluid in and old fluid out (as well as for thorough flushing), it is not strictly necessary for filling an empty system. If you can utilize some other method (shop vac, extra drains, disassembly, etc.) tho remove the old fluid, with a bit of patience you can refill the system through the expansion tank as described by Horigan.

The pump method follows Alde's original protocol as closely as possible, but as I've noted previously, there are many alternative ways that DIY owners have come up with that get the job done just as well. 

manyman297

@ScottG Thanks for the info. Maybe I'll go the non-pump route. At first the whole process seemed intimidating but it doesn't seem too bad (on paper). I was willing to drive it to Colorado or Nevada to get it done but now I'll probably just tackle it myself. 

bergger

The pump I used cost $15 off amazon and just made it easy and fast to get the glycol into the reservoir tank.  Especially if your tank is in the dinette porthole window.  If it is in the closet it's probably much easier to access and just pour it in.  You've probably already read this thread but just in case you have not here is a link to the Rhomar switch and my experience doing it.  

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

It does seem intimidating at first but you can do it.  I was so glad I researched it and got the courage to do it myself. Also if you do it yourself make sure you contact NuCamp afterwards.  If you have a 2021 400 that came with Century they will reimburse you for the cost of your materials. 

Parlando

Where is everyone purchasing the new Rhomar glycol. Do you need 4-5 gallons to do the exchange from the older Century to the new Rhomar.  I have a 2015 Outback without a bathroom. 

Parlando

And what costs are you finding for the Rhomar?  Thanks. 

RVMike

Parlando,, I bought a 5 gallon jug of Alde fluid from Apatche Camping Center in Portland, OR for $125.  It was May, 2022, I think.  I used about 2.6 gallons of it. I will used the rest at my two-year change out.  

For the flush, I used ScottG's instructions except I too used the 12v $15 electric pump from Amazon.   Note,  I had to use about 25 gallons of clean tap water until I was satisfied that the yellow color was gone.  l used tap water because that is what Airstream says, I believe.   Good luck.

Parlando

Thanks much. I appreciate it. That Apache dealer is now charging $675 for a flush. Wow.  

bergger

Do it yourself and save the money.  In our 400 I ended up using about 3.5 gallons of Rhomar.  As mentioned above and in the thread about doing the switch over just make sure you flush it out very well with water.  I used 15-16 gallons of water and tested the color of the Rhomar out of all the bleeder valves multiple times until I was satisfied it was the same color as the Rhomar in the jug. 

Parlando

Thank you Bergger.