AC vent air flow

[wdweldon]

On our 2014 Berk 390FL one air vent that is very close to the AC unit has very little air flow, is this normal?

[Maingler]

Yes, the vents closer to the air tend to have low air flow.

[Trappfarmer]

Anybody got a diagram of the whole ventilation system for two and three ac unit coaches?

[wdweldon]

Yes I would like a flow diagram also

[Maingler]

I posted this before but it gives you an idea of how it works.

[Trappfarmer]

Although helpful that diagram doesn’t explain why or how both or all three ac units share ductwork. If the rear ac is blowing, some of the air is exiting in the front of the coach. So how does the air get distributed in the maze of ductwork in the ceiling?

[Maingler]

Cold air ducts are 1 continous run from front to rear and sealed at both ends.

[Wolverine 1945]

Originally Posted by Maingler

Yes, the vents closer to the air tend to have low air flow.

With vents open ???
Max air flow !!!

[BigGuy87]

From my understanding, this is how most multi unit A/C ducts are layed out. Basically a racetrack with square cormers. Not a real efficient design and why racetracks aren't designed with 90 deg. corners and pit roads.

I'm assuming this is how mine is, as I have two parallel ducts running front to back that extend past the first and last vent on each duct and some air comes out of all vents with eiter A/C rinning independently. I plan on getting out the bore scope this winter to verify. (Image 1)

These images were pulled from th GD site and I plan on trying to replicate it on my 2 A/C unit system this winter. (Image 2)

While your checking things out, look for any air leak points in your A/C plenum and at each vent. Mine was blowing a lot of cold air into the ceiling atic cavity. Fiol tape is your friend.

Best wishes.

Mike

[wdweldon]

You would assume the ducts close to the A/C units would have high flow except on my coach the 2 ducts located on the front A/C have very little flow, is there an issue?

[Igave]

Mine are quite even, with not much variation it seems. That’s when both are running.

[Maingler]

The flow is highest at those vents and most of the air blows right passed. If you want to add a Deflector and it will force more air down in that location.