Length of Alde Rear Convectors

Tabaz

A friend has a 2016 320.  The two convectors located along the rear wall need to be replaced.  I measure 42" from fin to fin (the center pipe extends out from each side of the fins by a little over an inch).  However, the Alde parts catalog provides for a 39", 51" or 63" length.  Does any one know if NuCamp uses a custom size?  

fstop32

@Tabaz, I can't really answer your question but I can offer a possible solution so you can match the ones coming out.  The fins and mounting brackets on the convectors are just press fit connections so you should be able to order the next size up from what you need, say the 51".   Then remove the mounting bracket on one end, cut and remove a portion of the fins and reattach the mounting bracket.  You can then set the convector up on a miter saw or chop saw with a carbide tipped blade and trim the center convector pipe to length.  Make sure to clear any dust or aluminum shards from the inside of the pipe before assembly.  I used this process on one of my convectors that had corrosion damage.

Tabaz

What a simple solution!!  Thanks, we may do that.

fstop32

Actually, when I had to replace everything but the boiler in my 2015 I got new parts from Alde but was waiting on the rear convectors from nuCamp.  When it looked like that was an exercise in futility I just cut to corroded ends off my rear convectors, shortened the fins a bit and reinstalled them.  Since I was also replacing the hoses I didn't have to worry about plumbing back up to the now slightly shorter convectors.  I doubt I lost much heat output by shortening and I saved the cost of new convectors.
If you've got it that far apart I'd recommend BrianZ's idea to heat shrink the ends of the convector tubes.  I did that to all of mine, the new shorter convectors I got from Alde and my "repurposed" rear convectors.  It was 1" heat shrink, adhesive lined.  Got it on Amazon for $7.50 for a 4' length.

ScottG

It's never been clear to me how exactly the convectors are measured with regard to their catalog listing. Is it the length of the fins (where the actual heat exchange takes place) or is it tip to tip (including the stubs)? Might be a good question to ask of whoever you order them from--if you can find some to order...

Hitting the length precisely exactly is probably not all that critical as the hoses should offer at least a small amount of flexibility in either direction.

Denny16

The 39” replacement is closer to your original 42”, and the hose would makeup any difference.  The next size up (51”) is 9-inches longer, and might not fit without cutting, if the 51” would fit, it will give you more heat, but also reduce the fluid temp going to the other convectors.  The shorter convector will maintain a higher  fluid temp to circulate around.
 Cheers 

Tabaz

Fstop - will the stock Alde rubber hose clear the new larger OD of the convector end with the heat-shrink?   If so, that would be a great preventative solution.  Scott - my thoughts exactly!  Can't we keep this simple?  Denny - will be calling Elsie tomorrow first thing for the answer.  Thanks guys for all your responses.

fstop32

@Tabaz, Yes, the stock hoses will fit over the heat shrink treatment.  I expect a used hose will fit easier than a new hose.  All my hoses were new stock 22mm ID hose and fittings from Alde.  I put just a little bit of dampness from a wet towel over the shrink and inside the hose and was able to slide them on with a twisting motion.  Since I had extra clamps I double clamped each fitting making sure the outer clamp was up to the end of the stub of the convector on the theory that it would help keep the hose held tightly against the stub end and provide less room for anything to work between the stub and the hose.  If you don't double clamp I would suggest putting the clamp near the end of the stub, especially if you are not replacing the hoses.  You might be able to tell from the picture that I also was able to obtain some elbow fittings which help prevent kinking on some of the bends that had to be made.

fstop32

Also @Tabaz, if you do get into replacing hose you might consider adding a second glycol drain on the passenger side in roughly the same mirror location as the one on the driver side.  That will let you drain all the glycol that gets trapped in that area between the passenger bench convectors and the rear convectors.  If you have any questions don't hesitate to ask, I'm happy to help.

Tabaz

Fstop - thanks so much for the additional info. Will try the heat shrink approach with reserve. Can’t believe there would be that much extra clearance over the pipe.  As an aside, the four products that changed my life have been Viagra, post-it notes, rivets and heat shrink.  As the years have past, Viagra is in a distant fourth place while heat shrink is now in first.

fstop32

@Tabaz, both @BrianZ and myself have done the heat shrink treatment so we know that while it is a snug fit it does work.  One tip I failed to mention is to have an idea of where you want the hose to line up on the convector for final positioning then make your twisting motion work toward that final position.  Oh, and don't do what I did and forget to put the clamps on the hose before you twist it into place! 

BrianZ

Nice work @fstop32.  I like how you replumbed your passenger side to let that whole loop drain by gravity to your new drain.  NuCamp could learn something.

Denny16

On the 2022 TaBs, nüCamp is already installing a second glycol drain under the trailers, to use with their new pump system being used to drain, flush, and refill the Alde systems, reducing the required labor (and cost).
cheers

ScottG

@Denny16, to clarify, are you referring to the fitting that looks like two drains adjacent to each other, or are the installing a second low-point drain at a different location? 

Denny16

@ScottG, No, the two drains next to each other (actually one is a drain, the other is to pump glycol back in ), so the service pump can circulate the glycol through the Alde system, purging out the old and then refilling with the new glycol.  This works better than two drains, one one each side of the trailer.  That said, you do need the new Alde service pump to do this.
 Cheers 

fstop32

@Denny16, informational question here...I'm assuming that the 22mm hose containing the double drain fitting is just a straight through piece of hose.  It would allow you to pinch and close off the hose between the two drain stubs.  Is the Alde service pump process designed to pinch that spot off and pump fluid into one of the drain ports while catching the fluid being forced out (or sucked out) the other drain port?  Which stub you use for "input" is important so you don't try to force fluid through any check valves in the system in the wrong direction.  The pumping/draining process would push the old fluid out ahead of the new fluid being pumped into the system.  Once you've pushed out the old (based on color change or volume of draining fluid collected) the two drains are plugged and pinching tool removed.  I assume there would be some "leveling/topping off" to be done to assure that the system has the proper amount of glycol in it.
Is that a fair understanding of the automated fluid change process?
(I would plead guilty to any suggestion that this post maybe should have been in the "changing out the Alde fluid" thread 

ScottG

@fstop32, I have the same impression as you regarding the use of the double drain fitting.

Ultimately, the process is not all that different from what was done with the "old" Alde service pump. However, the old pump was attached via the expansion tank hoses, and awkward access made it far less convenient to use than the newer bottom fill design that (I presume) attaches only to the double-drain fitting on the outside of the camper.

When I was pondering different ideas for DIY glycol exchange, I considered a similar design incorporating a "fill port" just downstream from the existing drain. I abandoned the idea in favor of the @gregndeb adaptors, not because I thought it was a bad idea, but mostly because the adaptors did not require any modification to the existing system.

@BrianZ had the same idea, but he went ahead and developed a Cadillac version using a T-port valve on the fill port rather than relying on clamping the hoses.

However--getting back to your original point--none of these modifications will facilitate gravity draining the entire system, if that is your goal. Doing so requires at least one more drain installed at a different location at the low point of the convector loop.

fstop32

I concur @ScottG.  Since I was replacing everything I had no hesitation to change what had been.  The main hiccup in what I had was the passenger side "dead pool".  To me the second drain was a no brainer and for someone with a very little brain I jumped at the idea.  I laid in my lines so everything has to gravity drain to one side or the other with no low loops.  Barring a vacuum in the boiler it too should drain all but the small amount that might sit in the bottom (which maybe a quick jack up the passenger side might resolve).  Refilling was easily accomplished using the new drain (it would also work from the driver side drain too).  Topping off and burping is something that would have to be done no matter what the process.  I'll be interested to see how much of my glycol drains out the next time I do a change, I know exactly how much went in.
I do wonder what Alde or nuCamp does with the overflow and drain line on the reservoir.  Do they use a different cap when they are pumping to keep the reservoir from backing up and spilling over?

ScottG

fstop32 said:

...
I do wonder what Alde or nuCamp does with the overflow and drain line on the reservoir.  Do they use a different cap when they are pumping to keep the reservoir from backing up and spilling over?

I've wondered the same thing. Of curse, this all assumes my understanding of how the bottom fill pump works is correct.

BrianZ

@fstop32, when I saw that double T valve you posted, I was picturing that being the functional equivalent of the original drain T, plus my 3-way valve that I installed inside on the same line:

When the handle on my valve is straight up, the flow is straight through like (1); when to the left, it's like option (2) where injected fluid flows into the Alde pump line; and when valve handle is turned to the right, the flow is like (3) where flow fills the drain line and expansion tank reservoir (with drain closed).
One difference is that I don't need to pinch any tubes, and my valve control and filling is done from inside.
While I cannot expect to do a thorough gravity drain without a second drain in the convector loop, I figure that I won't need to, since a complete flush can be done by pushing old fluid out by pumping new fluid into the system through the 3-way valve in position 2, then filling the drain line & tank using valve position 3.  I assume this new double T fitting can accomplish the same.
Thanks, @ScottG, for sharing your idea of a fill port downstream from the drain - that made a lot of sense to me, so I just needed to find the right kind of valve.  The one I used was just a bit small at the barbed hose fittings, but a couple layers of heat shrink tubing gave me a snug fit inside the Alde rubber hose.
I don't know how the new Alde pump system works, but I also had reservations about pumping into the system and possibly overflowing the expansion tank or through its overflow/air tubes, but these fears were unfounded.  With my electric pump running continuously, the fluid pushed into the tank drained out the drain line just as fast as it went in & never filled up the tank while the drain was open.  I then back-filled the drain line & tank from the new 3-way valve.  Maybe Alde's pumps are more powerful & a greater pressure/flow rate might still be a concern - I don't know.