Alde Diagram for 2021 400/Bleed locations

LonesomeRoad

Does an Alde heating diagram exist for a 2021 400. I spoke with Alde tech support today and described an issue to them (no heat under the dinette) and they said that NuCamp's solution to me (to increase the heater setting to 4 on the Alde, not the Flow) would not fix anything and that I needed to bleed the system but I don't want to just start taking things apart to locate bleed locations. The only obvious one to me is under the sink.

LonesomeRoad

Subsequent to the above comment, I decided to explore a little. The main issue was limited heat under the dinette. It ends up that, even if there is a convector there, that the ducting for the A/C is immediately under the cutouts (vents) below the table so not much warm air is going to move along the front wall. I tried to illustrate this below.

pthomas745

This might not help a lot, but this thread shows where the new fangled "bleed valve" is on a 320.

https://tab-rv.vanillacommunity.com/discussion/13245/newer-alde-bleeder-tube-location

pthomas745

Here is another quote from a thread about a 400 (I think!).

"If you pull the cover off just under the shower you will see a radiator. The radiator has a bleed valve. That radiator is the highest point in the Alde loop and where air tends to gather."

manyman297

@LonesomeRoad I can’t find my post but this issue was brought up a couple of months ago. I noticed that our AC duct covered the exhaust vents under the dinette too. They seem to be glued to the underside of that vent. In older models Nucamp put a shroud around the AC duct so the hot air from the convectors would rise around it and out the vents. I don’t know why they stopped doing this in subsequent models but why completely cover that vent? Seems like a bonehead move in their part.

Also, if you stick your fingers up under the cutout between the floor and buildout wall (under the dinette) you can feel the connector. It’s there and working (the heat radiates through the wood) but can’t reach the vents due to the ductwork that’s in the way.

pthomas745

@manyman297 I think this is your post:

https://tab-rv.vanillacommunity.com/discussion/13927/alde-vent-blocked-by-ac-ducting

manyman297

Yup, that's it!

LonesomeRoad

@manyman297 and @pthomas745 thanks for that link. Wonder why I could not find that in a search. I kept thinking that I needed to bleed something up that way and finally figured out the issue with the ducting being in the way. Will digest the info in the above link. Thanks again.

manyman297

@LonesomeRoad Was your ducting attached with glue to the underside of the wooden box under the dinette? It appears mine is and it literally covers the vent so none of the hot air can escape. If you look at the screenshot from the factory tour you can see the older models had some kind of shroud around the ducting to allow the hot air to rise around it.

LonesomeRoad

@manyman297 I only removed the passenger side bench cover and not the 'middle' cover so cannot say for sure, but I did feel around the top of the A/C ducting to see how pliable things were and it felt like it was pretty much stuck in place, so probably glued or tacked in some other way. I've read posts of people talking about how much heat they get from the middle convector and when we did not experience that, figured I had another issue (air in lines or a leak). Now it appears that, given the current installation, having a warm box under the dinette is as good as it will get. The convectors under the two dinette windows really kick some heat, so I'm leaving well enough alone for now! When we first got the camper home I did find glycol running down from the expansion tank (and was even on top of the driver side bench under the cushion). I cleaned all that up well, removing panels as needed, and found the expansion tank lid was not very tight. After two trips now, I have not seen a repeat of that. OTOH, I'm regularly removing the Alde & plumbing cover and tightening fittings after each trip -- having read of too many people seeing black tank flush leaks, etc. All three times I have done this, I have found fittings that needed a little more tightening. Also used teflon tape under the sink to stop a small leak there which worked out just fine. Ah the joys of camper ownership!

bergger

We have an early production 2021 400 and on our last trip I also noticed no heat coming out of the top cutouts under the dinette.  But the lower box was a little warm and we had heat downstream so I knew it was not an air block.  When we got home I opened up the dinette area and yep, the duct work totally blocks the cutouts so no heat escapes.  And yes it is glued or fastened somehow in place.  And it's really just too large to move anyway to let heat escape.  I'm sure the system worked fine when the used the Air8 but not so well with the cool cat.  And all they have to do is router the cutouts on the front part of the top panel instead of against the front wall where the duct work is!   The space above the heat convector is open with only some wires running above it. I sent an email to NuCamp letting them know to do this if they have not already done so.  I'm tempted to cut some holes in mine but don't want to make it look ugly!  Also I have to say the dinette panels are very well screwed together!

I also noticed that it looks like there may be a a bleed location behind the dinette seat on the door side.  I noticed a plastic tube/pipe running up from the alde lines and disappearing somewhere near the port hole window.  It looked like it was full of green fluid so I can only assume it is glycol. 

LonesomeRoad

@bergger Please let us know if you hear anything interesting from NuCamp.

bergger

I emailed Austin about this and he thanked me and was unaware of it. He passed in my suggestion to their R&D team. In the meantime I might just router a few cutouts in the box to let the heat out. 

Denny16

@bergger. We have a 2018 TaB 400 with the Cool Cat AC, and the large AC duct under the center box under the dinette is how all the 2018s are made, except for the 2020, which has the Air8 under the rear bunk.  I have the same arrangement as yours, and heat manages to come up from the front top slot under the dinette.  The Alde convector is under the duct, Nd Coo, air is drawn in from the bottom slot and heat from the convector causes the air to rise and allow warm air up and out the slot.  It is not a direct flow but rather come up under the duct where the convector is and rises up and around the front ofmthemAC duct, not behind it, which as you noticed is somewhat blocked against the front wall.

Heat is a passive flow, not forced, so not really noticeable.  I placed a small USB fan on top the Alde/AC duct cover box, and it draws the heat up and into the cabin for a little added air circulation.  Here is the photo of the front dinette Alde box partially removed (you can see the AC duct is against the front bulkhead of the trailer, but there’s room in front of the AC duct and above it for warm air to flow around and up):

manyman297

You can see this plastic shroud they used to use to house the duct and keep it away from the vent. No such thing on our 2021 

LonesomeRoad

@manyman297 - Am guessing that the change from the Air8 to the Cool Cat was done in a hurry and without thinking things all the way through? Although, since the Cool Cat was used before they must have routed it differently.

manyman297

That video is of the 2019 400 I think which used the cool cat (you can see it on the right) so it should be routed exactly how ours are. I don’t know why they omitted that shroud though. Parts availability maybe? 

I also wonder how well that vent really heats the space even if it isn’t blocked. Considering you have the table above it, the warm air flows around the sides and only heats the sides of the front window. We’ve yet to use the camper in really cold weather so I can’t speak to that. 

At some point I want to open up that space and see if I can’t somehow push the duct up where it should be.

Denny16

The 2018 (at least our late Jan 2018 build) does not have the the AC hose shroud either, heat still comes up and out @manyman297.  Not sure what is going on with your unit.  But you are correct, it is not a lot of heat, but enough to warm you up whilst sitting at the dinette or sleeping on the dinette bunk (warms the bed nice).
cheers

manyman297

I just need to open that compartment up at some point. I know there’s room under there. Not sure why they chose to attach it right in the way of the vent.

bergger

When I opened ours up there was not enough room to move the duct work to allow the heat to escape. We get no heat out of the vents cut in the top of the box as it is completely blocked by the duct work. Since there is open space above the convector I may just router some cuts in the box above the convector to allow heat out.  This is what they should do going forward.  We live in a cold climate and a little heat under the table would be nice for the legs and feet. Above the table the heat is great. 

bergger

While poking around our trailer today on an unrelated issue I also found a bleed location on the convector that is behind the kitchen.  If you open the round compartment under the sink you'll see and birch bulkhead wall.  You can reach behind it and feel the bleeder valve on the end of the convector.  Last time I looked at a 2022 400 I looked under there and saw they now added a plastic tube than has the bleeder valve on it so you don't have to reach down there or take the bulkhead off to get to it.  

Edit.  I also found one at the end of the long convector behind the bed on the door side.  But you have to remove the long back panel to access it.  It's attached to a clear tube about a foot long.  So at this point I have found 4 bleed valves in the 2021 400.  

Denny16

Good to know, will check out our late 2018 TaB400 to see if they are there.
cheers

bergger

I looked at all of our convectors in the 400 yesterday to check for any signs of bulging and all looks like it good and brand new.  Just a exterior visual of course but absolutely no bulging.  Anyway I did confirm the 4 bleed valves in our 2021 400.  Behind the bed door side, behind kitchen sink side, behind the door side dinette seat and in the bathroom under the shower.  None of them are super easy to access but certainly can be if necessary.  

On a side note how do you expose the Alde lines and bleeder in the bathroom?  Do you just need to remove the top two screws in the vent or does the whole cover pop off somehow?  

Robermcm

For someone finding this thread in the search for bleeder valves in more recent 400’s, I’ll answer Bergger’s question above - yes, the access to the bathroom bleeder is by removed the two hex screws on top of the metal register. A small cap comes off, not the entire front. It’s right there. ,righty righty. Lefty loosey. 

I have air in my system. I loosened the bath valve and no glycol comes out. No matter what tilt the trailer has. So I’ve found the air. 

Robermcm

From what I learned about bleeders in the 2021 Tab 400. Hoping they’re in the same spots on the 2023. Reservoir is accurate for 2023. In the 6” space on drivers side. So are the bath radiator and under sink bleeders. Need to confirm rear bed and dinette bleeders. 

Robermcm

So I found one of the two reported bleeder valves in my 23 400. The rear passenger side one. The front dinette passenger side was no where to be found. Possibly under portal window if you take off the side panel to the left of the door as you’re looking at it from inside. 

Robermcm

Updated picture. Tab 400 Boondock,

subkron

@Robermcm For the rear passenger one in the latest pics, can you access it for bleeding by just reaching in or do you need to remove the panel as mentioned earlier in this thread?

bergger

You can reach down to access the one in the corner behind the bed.  

swiftwave

It is perhaps worth mentioning that my 2020 T@B 400 Boondock Lite (Build Date: 09/2019) does not have Alde bleeder valves in three of the above mentioned four locations.

My T@B does have a bleeder valve under the shower, but not in the other three locations in the diagram above.  I removed panels in all three of these locations to gain access; no bleeder valves were found.

I have no idea if this is typical for 2020 T@B 400s.  Do you know if this is typical?

bergger

I do not know for sure but my guess is that your configuration is normal for a 2020 and earlier model.  They seem to have added bleeder features such as valves and tubes in later model years.  My early production 2021 400 has all the bleeder valves mentioned in this thread but only has a bleeder tube on the location behind the bed and on the location behind the dinette wall by the door.  We have no bleeder tube located under the sink.  That one was added on the 2022 models or possibly late 2021.  They will make running changes on occasion during a model year.   If you wish to add a bleeder valve you can always do that.  You'll just have to drain the system and get the appropriate hose and or bleeder valve.  From my experience draining and refilling my system, I removed most of the air from the bleeder valve behind the bed and in the bathroom.  Not much had collected in the other locations.