Alde service

justdoit70

I was thinking about doing this with the alde. Fluid change 21 400 
1 Uncap  the tank.
2 Remove Red plug under trailer.
3 Let drain in a clean bucket
4 Measure the amount of Rohmar fluid drained.
5 Compare to what system holds, I am not sure of the amount of fluid in the system.
6 If the amount of drained fluid is very close to system capacity would it be safe to just refill and call it done.
7 If this way would work I would replace at a yearly interval.

I had it done in 24 at my dealership.
I am looking for any input or tweaks
Thanks for your time.

2021 t@b 400 boondock

AnOldUR

Did my 320 about a week ago, so there may be some differences, but I followed close to your procedure. What I found was that by just draining I did not get enough out. I disconnected the hose by the check valve and forced air through the system. This got all but a small amount of fluid out.

pthomas745

The "drain and refill" method that you describe in your post has been done by many owners in the past, especially after around 2018 when nobody anywhere could do a Alde glycol exchange. 

It would be interesting to find out how much you clear with just the drain, since their are various areas of the glycol "loop" that have to get back to the expansion tank before it can drop from the drain.

I did the same thing as @AnOldUR did.  A few minutes of blowing through the hose after the check valve shoved the glycol around to the drain.  The only glycol left in the setup after that was probably between the expansion tank and the inside of the Alde.  We can show you the spot where to find the check valve, etc.

Horigan

@justdoit70,  If you're 2021 is like my 2019, which I suspect it is in this regard, you'll drain a little over a gallon from the red drain plug, but the capacity is 3.5 or 4 gallons.  So you'll only be draining a third of the capacity.  This is why we all go through the shenanigans using pumps or shop vacs to pull out or replace the remaining fluid.

AnOldUR

Horigan said:

... the capacity is 3.5 or 4 gallons...

edit to say, my mistake. I just noticed that this is for a 400 ...

I've seen those numbers thrown around, even from some nuCamp sources, but it seems high. I've read that the furnace capacity is about a gallon of glycol, so even with a quart in the expansion tank, that would leave around 2.5 gallons in the plumbing. If my math is correct that would be about 80 feet at .875 inside diameter.

The reason I question this is that (even though I've altered my system) I drained less than two gallons. After draining I dismantled a lot of the system, so I'm pretty certain it was mostly empty. That would mean maybe 30 feet of plumbing would get me to the two gallons, which sounds about right.

I'm curious how much others have been able to drain from their 320 Alde systems?

For anyone else with a 320, I found this over four year old post that agrees with my math ...

ScottG said:

If we're gonna' talk math...

The documented boiler capacity is 0.92 gallons. Approximately 33' feet  of 22mm I.D. hose/convector (standard 320 without third convector) will hold another gallon. Maybe add another pint depending on how full your reservoir is, and the calculated system capacity should be right around two gallons.

manyman297

Curious as well. I always thought the 4 gallons called out for capacity seemed high but I didn’t chance it and just refilled the system with 4 gallons. 

justdoit70

@pthomas745 Please show where the check valve is . Also thanks for everyone’s comments. 

AnOldUR

I'll try to save @pthomas745 some work, but this is for a 320. I'm not sure if it's the same in a 400. It may help someone else who's following this thread.

Horigan

manyman297 said:

Curious as well. I always thought the 4 gallons called out for capacity seemed high but I didn’t chance it and just refilled the system with 4 gallons. 

I'm able to fully drain my 2019 400 system with a shop vac (reservoir in the closet).  When I refill the system it takes a little over 3.5 gallons.

justdoit70

@Horigan With that said I am assuming .Pull the red plug under trailer and proceed to the glycol tank and apply shop vac to the tank to pull remaining glycol out correct? Does this involve the check valve that was mentioned by@AnOldUR.
Thanks.

Horigan

@justdoit70, When you drain with the red plug, only one of the hoses to the reservoir is drained.  The other remains full due to the check valve.  I remove that hose and duct tape it to my shop vac hose and pull the remaining fluid out that's held by the check valve.  Hope that makes sense.

justdoit70

@Horigan Makes sense .This loop will be the longer one I am thinking. Do you use a smaller  sized shop vac or the ole 5 gal stand by with the 1 1/4 hose. Thanks waiting for April here in Northeast Pa.

AnOldUR

Not that I think that one way is better than another, they both should accomplish the same thing, but rather than trying to suck fluid into the shop vac, I remove the check valve and blow into both tubes to clear the lines. Forcing air into the furnace side pushes a lot of fluid out toward the low point drain where it runs out.

Horigan

justdoit70 said:

@Horigan Makes sense .This loop will be the longer one I am thinking. Do you use a smaller  sized shop vac or the ole 5 gal stand by with the 1 1/4 hose. Thanks waiting for April here in Northeast Pa.

I use a Ridgid 3 gallon shop vac with the 1.25" hose end.  I just use a bunch of duct tape to connect it to the hose.  It's really easy when you have the closet version 400.