TAB 400 Alde Glycol Routing = questions =

MuttonChops · January 31

Background
I'm considering replacing a '18 320S with a '25+ 400 and am trying to get educated on the trailer differences.

Issue:
The TAB 400 has a larger glycol 'heater' loop.
Air Force Guy factory tour videos are dated and don't cover everything plumbing/electrical/Alde 'behind the walls'.

Request:
For those of you that have dug into the TAB 400 Alde 'heat', please review/edit/comment on this draft diagram that outlines the TAB 400 Alde Glycol Loop.

TIA
& used a new-to-me drawing tool so forgive the overall quality.

02-11-26 Diagram Removed, updated version posted later in thread

dsfdogs · January 31

In the bathroom, there is an element under the floor plus the one on the wall below the shower handle. I don't know direction of flow, but I could always feel the heat in the bathroom first, also in the cubby on driver side near expansion tank. The others were much more elusive.

qhumberd · January 31

@MuttonChops Other than the location of the expansion tank, which is in the closet in my 2019 400, the diagram is correct from what I have inspected. In the bathroom proper below the water controls is an arched metal pipe that heats that area, and then it exits to the expansion tank and from there to the boiler. Under the bathroom floor in mine is a typical aluminum convector. I have one bleed point at the arch in the bathroom. I know that newer models added bleed valves at other locations. Your flow is correct for my unit.

pthomas745 · January 31

This is a thread from a couple of years ago with pictures and descriptions.

https://tab-rv.vanillacommunity.com/discussion/18266/t-b-400-convector-locations

MuttonChops · January 31

pthomas745 said:
. . . thread from a couple of years ago with pictures and descriptions.

Thanks.
I searched with several keywords and never found it

manyman297 · February 1

Don’t forget about the manual bleeds on the rear/bed convector, the kitchen convector and the passenger dinette.

MuttonChops · February 2

Thanks to everyone for the comments/clarification.
The link @pthomas745 proved to @bergger 's detailed reference pictures was very helpful.

I've got what I need for now - - - will update/customize if/when a 400 is purchased.

For your entertainment:

02-11-26 Diagram Removed, updated version posted later in thread

B0atguy · February 2

There are 6 convectors in a 400 . You missed the one that is adjacent to the cool cat area in your final drawing - Left side , front of the 400 - dinette seat area . The heat from that one goes up into the window cavity .

This thread shows pictures of each convector quite well .
https://tab-rv.vanillacommunity.com/discussion/18266/t-b-400-convector-locations

MuttonChops · February 6

Minor update . . @BOatguy . . caught one missing on driver side

02-11-26 Diagram Removed, updated version posted later in thread

manyman297 · February 7

I believe you’re still forgetting the bleed valve on the passenger dinette convector.

Horigan · February 10

My 2019 400 has two hoses going to the expansion tank, inlet and outlet. Did that change to a single hose on later models?

MuttonChops · February 10

Horigan said:

My 2019 400 has two hoses going to the expansion tank, inlet and outlet. Did that change to a single hose on later models?

Most posts comment or show Two Hoses to the expansion.

Another item missed in my Draft Diagrams

From @bergger post on locations, pictures

Image: https://us.v-cdn.net/5021717/uploads/editor/6i/b3uogr9yrquk.jpg

MuttonChops · February 12

Here is my current diagram version
for your reference and entertainment
Time to work on something else

Image: https://us.v-cdn.net/5021717/uploads/editor/0c/szodk11nv8p0.png

Attached PDF file has the above diagram and a few basic 3D images

TAB 400 Alde Glycol Routing = questions =

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