A/C Ceiling Ducts

[SpursMVP]

Okay...so I was in our HR today getting ready for our trip next week and had the generator running to check out the A/C.

Although our twin units keep the HR very cool, I noticed that there is little to no airflow coming out of the streetside vents.

I pulled a few of the ducts to see if there are blockages in them....nope. Checked the filters again and I just replaced and cleaned them a few months ago.

Could there be an obstruction in the ceiling ductwork? If so...how does one go about getting rid of it?

[fxdave]

i checked mine they wernt working come to find out all air was escaping though the seal in the roof vent we retaped an now good to go

["007"]

If you have two rows of vents one row would be the return, thats how it works on mine.

[nodine]

Quote:

Originally Posted by SpursMVP Okay...so I was in our HR today getting ready for our trip next week and had the generator running to check out the A/C. Although our twin units keep the HR very cool, I noticed that there is little to no airflow coming out of the streetside vents. I pulled a few of the ducts to see if there are blockages in them....nope. Checked the filters again and I just replaced and cleaned them a few months ago. Could there be an obstruction in the ceiling ductwork? If so...how does one go about getting rid of it?

If you can find someone who has a pipe inspection camera I suggest you fish it down the ducts to check for broken seals and obstructions.

Bob

[wizzo442]

SpursMVP: My 06 Diplomat had the same problem. I removed the entire plastic A/C cover inside the coach. There are 4 screws under the filter area and two under small (3/4") round plastic covers that must be removed with a sharp knife or screwdriver to access the screws. There are 2 openings about 4" x 5" on either side of the plenum (the area that the squirrel cage fan blows into). The one on the road side of my unit was covered with foil tape. I removed that tape and the roadside vents now work much better. They do not move air like the curb side because of the direction the squirrel cage fan rotates, but they work better. Hope this helps.

[itdave]

I just did some work on mine and here are a couple of things that might help. My street vents are not in a straight line from front to rear. I found that where the duct jogs around the shower the air was leaking into the overhead. I could not inspect the duct so I just put a piece of foam into the duct blocking the air from the front A/C from reaching the rear vents. This did a lot to improve air flow in the front street side vents. The other thing I did was to remove all the vents and cut off part of the collar that goes up though the hole. I found that all the collars were about 1/2 inch longer than they needed to be. This creates some blockage in the duct and prevents air from exiting the vents. Finally I am working on replacing the air inlet filter with a larger standard furnace filter. Hope this info helps

[SpursMVP]

Thanks gang....this is some great feedback. I was trying to figure out how to access the output vents from the unit. Ended up on the roof to check things out; however there's not much access under the A/C roof cover.

I'll check under the internal plastic piece as suggested. It's just weird that the curbside has such strong flow and the streetside is almost non-existant.

[Sixpack98]

Some very good suggestions above. I was able to increase the air flow by trimming down the duct tube. Another poster noticed that the round tube from the vent set very high in the plenum and suggested that trimming it down would increase the air flow. The round tube it seemed acted as a baffle impeding the airflow and trimming it flush appeared to increase the amount of air delivered to the coach. I took their advise and while not a huge incrase the amount of air was much better and the coach was a little cooler.