Rear wall sweeting

[traindrv]

I have a Columbus RS 320 and with the AC running the outside rear wall sweets between the clearance lights and the roof, anybody had this issue or any suggestions to remedy the issue.

 

[jayrodoh]

I'm not familiar with that exact model but usually there is a duct in the ceiling for the AC. I suspect it's not closed at the end and allowing cold air to exhaust towards the back wall in the ceiling. This will cool the outside wall and cause moisture in the warmer outside air to condensate.

See if you can pop the farthest/last ceiling vent off and stick your cell phone camera up in there and see. If it's open, you can seal off the duct through the vent with some spray foam. Make sure you do it from the last vent inline though!

 

[5picker]

I'm not familiar with that exact model but usually there is a duct in the ceiling for the AC. I suspect it's not closed at the end and allowing cold air to exhaust towards the back wall in the ceiling. This will cool the outside wall and cause moisture in the warmer outside air to condensate.

See if you can pop the farthest/last ceiling vent off and stick your cell phone camera up in there and see. If it's open, you can seal off the duct through the vent with some spray foam. Make sure you do it from the last vent inline though!

X2. Great advice!

 

[mjones12]

Good idea with the phone.

 

[ependydad]

I agree. I used some of the silver HVAC tape to tape off the end ducts. Same concept as the expandable phone- just close it off so you aren't wasting cold air!

I did the same on the floor with the heat vents. That made a huge improvement.

And, it has the added bonus of having the tape on hand to fix the air conditioner. Before we had a lot of leak over from the cold air to the return side.

 

[jayrodoh]

Here's an example of what is usually in the ceiling. You can see the box end here, imagine if it wasn't capped!

 

[traindrv]

Thanks for the suggestion, I was thinking that is the problem. I had thought about pulling the AC unit and going at it that way.