Alde - Automatic Air Bleeder Valve - Improper Installation

Bayliss

If you have not already seen it (I have not yet seen anyone mention it up to this point), you should watch this YouTube video about the Automatic Air Bleeder Valve.  It was created by Mark Turney, who is a member of the T@B Facebook page.  He has other T@B repair and maintenance type videos on his "T@B Trailer Upgrades and Maintenance" channel, so it is worth subscribing to.

On this particular video, Mark demonstrates how the Automatic Air Bleeder Valve works and why air is not properly being expelled from the glycol lines.  The reason?  BECAUSE nuCamp did not install it correctly on some trailers.  As Mark points out in the video, the valve needs to be installed in a vertical orientation to work properly.  There is even a plastic clip attached to the exterior of the Alde boiler, which is where the glycol line downstream from the Automatic Air Bleeder Valve is supposed to be attached to keep the valve properly oriented.  I looked at my valve and it is close to vertical and the glycol line is properly resting in the plastc clip as designed.  However, I have seen photos posted by other members on this forum that depict the valve sitting at a significant angle.  My guess is that is why some owners have found that they have to bang hard on the valve to get it working again. 

The video was quite a revelation to me and explains why folks keep having issues with the valve.  Definitely worth a look!

https://www.youtube.com/watch?v=mUZ8u6Mxsf0

Sharon_is_SAM

Makes sense.  I wonder if this is common in the 2015 TaBs?  Ours is vertical.  He kept saying water, but it is really air bubbles in the glycol.  

db_cooper

Our 2015, they used the clip to hang the extra power cord and our valve hangs down.  It's not been an issue for us, system has always been quiet.

Bayliss

Could be, @Sharon_is_SAM.  They must have caught the problem somewhere down the line in model year productions.  The below photo of the Automatic Air Bleeder Valve was taken in April 2019, about four months after I purchased my 2019 320 S.  You can see the glycol line properly resting in the plastic holder.  If you look close, the white plastic is visible around the lower part of the aluminum connector between the rubber glycol lines.

Tabulating

There is something more going on with the bleed valve than the incorrect installation.

Our valve was properly installed on our 400 but went bad within 18 months and was leaking a little bit of fluid all the time. 

I just put a clamp on on the bleed line that goes thru the floor to finish up the trip.

When I got home, I disassembled and put in a new valve. It has been fine for about a year.

It was a very informative video and that install could definitely lead to empty tanks.

Sharon_is_SAM

Lots of cases of the Air Bleeder Valve sticking open resulting in loss of glycol.  That flow assembly is a weak link for Alde.

jkjenn

I had an early 2015. Mine appears to have been mounted so the bleeder was at a bit on angle, as well. I never had an issue with the Alde, apart from the exhaust hose jiggling loose one time.

Sharon_is_SAM

So, if you keep the glycol expansion tank appropriately filled and keep the glycol pump rate lower, where does air have a chance to enter the system besides a stuck open bleeder valve?  

ChanW

The air in the Alde hydronic system comes out of the fluid naturally when the fluid is heated. This "air separator" is designed to allow that air a place to exit the glycol's plumbing. It's really designed specifically for the small amounts that occur from heating the fluid.

So, to answer your question.... (Or was it rhetorical?) Just from heating the fluid...

Sharon_is_SAM said:

So, if you keep the glycol expansion tank appropriately filled and keep the glycol pump rate lower, where does air have a chance to enter the system besides a stuck open bleeder valve?  

ChanW

You know, this is an interesting point, and I wonder if the tilted, inoperable air separator is related to the corrosion problem.

Sharon_is_SAM

Thanks @ChanW.

ScottG

The expansion tank must act as a sort of air bleeder as well. I can tell you that after I changed my glycol, that's where the bulk of the air trapped in the system came out in two big burps.

In thinking about it, it does make sense why the air bleeder is where it is. There are high points on each end of the the convector loop (that's why it doesn't drain on its own). One is at the the expansion tank, and the other is where the loop exits the top of the Alde--right where the bleeder assembly is installed. 

Basil48192

Great information.  I have a 2021 321S and the hose is installed correctly (horizontal and secured in the clip).  However, I'm always glad to learn more about the system.  Thanks for posting!

Verna

For those of us who have had T@B’s since the 2014/2015 era when Pleasant Valley Teardrops (now known as nüCamp) started using the Alde, there was a common complaint that this air bleeder valve touched the bottom of the plywood for the seat and the valve was hot when the Alde was in use. 

I wonder if the nüCamp factory started bending them to the side to alleviate any contact with a flammable object?

Denny16

It does not get that hot, to catch the plywood alight.
cheers

ScottG

This at least explains why the connector between the air bleeder and the outgoing glycol hose looks different in different pictures.

Mine looks like the one in jkjenn's photo above. The rubber hose is way to large to fit in the supplied plastic hanger, so I never gave it any thought.

In Bayliss' photo above, it looks like the hoses have been separated a bit and the aluminum fitting (which may also be the non-return valve in newer models) is slotted perfectly in the hanger.

ScottG

I finally got around to watching the video posted above. Seems like this guy did his homework and offers a good explanation of why the auto air bleeder should be mounted horizontally.

I also have a 2015, but mine lacks the driver's side convector. As a result, I have a little more play in my glycol hose, and was able to properly mount the air bleeder assembly in the plastic hook as was the original design.

However, as @Verna suggested above, this put the top of the brass air bleeder valve about 1/4" higher than the Alde in a location where it would contact the bottom frame of the seat cushion. While I doubt flammability is an issue, I didn't like the idea of the cushion frame putting constant pressure (however small) on the valve, hoses, and fittings. I'm thinking I will cut away a bit of the seat frame just enough to allow the valve to maintain clearance when in the proper horizontal position.

Note that this is a two-part video. In Part 2 he mitigates the problem by rerouting the hose to the driver's side convector. He does not address the issue of contacting the seat cushion.

As an interesting side note, if you watch the Part 2 video at about 8:15 you will see the green deposits and early corrosion (he calls it "tarnishing") on his convector fittings.

ScottG

Here's my mod to the seat cushion, inspired by other comments posted here. The underside of the seat has an addition (and ample) 7/8" of headroom, except for where the frame members are. Unfortunately the central frame member landed on top of the repositioned air bleeder, so a little more clearance was called for.

In a nutshell, I widened the center support with an additional board then cut a 3" hole centered exactly above the bleeder. There was no need to cut into the plywood base or the cushion itself, only the frame.

The extra piece may have been overkill but was easy enough to add and made a nice rim to reattach the bottom fabric around the hole. I attached it with dowels on the lower (back) edge, and pocket screws on the top (front) edge.

ChanW

Nice fix @ScottG. I've wondered if I should fix that for years!

pak

Reporting from the CS-S side. My bleeder works fine and is in the plastic bracket however it is tilted at about the 1 o'clock position toward the alde. Currently, it is a 'if it ain't broke' situation. The bleeder is not connected with connectors so that the bleeder could be rotated to verticle. The hose section is not twisted and looks to have been designed for this. Most likely not, however. There is more than enough clearance for the bleeder to clear the cabinet lid. I will leave it as is and perhaps change it next time. Getting quite a list to prepare for the next change

ScottG

Good info, @pak. I get a sense that the assembly can be twisted a bit on the downstream connector--that might explain why yours is positioned as it is.

I should add that I've never had a noticeable problem with air in my system in the six years the bleeder assembly was pointed downhill. I just figured that since I had Alde maintenance on the brain, I'd correct this little issue as well.