Isolating 1 AC unit

[Randy E]

We have a 2017 3791RD. The 2 AC units are ducted together and cooling the front bedroom on 1 AC is all but impossible in hot weather. Sometimes while traveling we have limited power (30 amp) and for just a quick overnight we don’t need to cool the entire coach. It was 97 deg outside. And running 1 AC unit I can maybe get it down to 85 because half of the cold air is going to the kitchen and living room that we are not using while sleeping. Has anyone ever been successful in installing a baffle in the central duct system so cold air could be blocked off from the kitchen and be circulated in the bedroom ? Being that AC unit has its returns in the bedroom, it should circulate good. This way we could cool down the bedroom only at night. It takes a long time to cool such a big space it extreme heat. I think this could be a solution for a quick stop overnight on limited hook ups. If anyone has done this can you share how it was accomplished please?
As always. Thank you all. I enjoy reading all the posts.

 

[Daryles]

We bought this one for the bathroom so we could close it when necessary.
Maybe install them in the living room and open/close them when you need to.

THETFORD RV Camper 1.5 Flange https://a.co/d/gwjLVju

 

[Bourbon County]

I agree about limiting air flow to bathroom, due to their location along the duct system, they get way more air than needed. This would be another good option:
https://www.etrailer.com/RV-Vents-and-Fans/Valterra/A10-3354VP.html
This one is adjustable and I believe you'll find the room stays cool with this closed as far as it will go. The idea is to restrict bath air flow and push it back to vents in the bedroom.

I don't guarantee this but might be worth a try. Run the rear unit fan only while running the front AC. The racetrack duct system just allows the opposing air streams to meet somewhere in the middle, this might just keep the cool air pushed back into the bedroom. Running fan only draws minimal current and you should be good even on 30 amps.

 

[Randy E]

Thank you both for the good ideas. I didn't think of swapping the vents out. That is probably the easiest solution to my problem. I wish the bedroom AC unit was the old style that just dumped out the bottom. I've always had issues in keeping the room cool even on 2 AC units. I already opened up the return ducts by inserting PVC tubes inside to hold the duct open. That did increase air flow. Now I just need to control where all that flow is going. Thanks again.

 

[Bourbon County]

Thank you both for the good ideas. I didn't think of swapping the vents out. That is probably the easiest solution to my problem. I wish the bedroom AC unit was the old style that just dumped out the bottom. I've always had issues in keeping the room cool even on 2 AC units. I already opened up the return ducts by inserting PVC tubes inside to hold the duct open. That did increase air flow. Now I just need to control where all that flow is going. Thanks again.

I seriously doubt either of those ideas would qualify as a solution. At best maybe contribute to a cumulative effect. You mentioned the return ducts, are you still using the black foam filter element that came with the rig? That material is pretty restrictive even when it's clean; buy a sheet of this:

https://www.amazon.com/Size-Filter-Size-Replacement-inches/dp/B0F53Y8BFM/ref=sr_1_11?crid=31E2V8II6XPNU&dib=eyJ2IjoiMSJ9.w9eLYESivRdkGVRLzXL9zJ8OK8PocYMF6OR3PKtKzu1VnuzQgnyQR4EN2C9Gu2L9FKZVj2Ll8tXc8-fnVam3VicfeGCLdw4q3agXRNMxKaFsymecodQC9rECvIocouYpvqYr6Y_Ua0i02Lw_NF7V26Za8eOBNE7scVMnwhd-uDrrauEhyc1ffrDJjAI5brjO28n9mPodLTfwH3yX9CEbbjgtXZVk2-HVDldxlsU-FYw.yVc8ZhuBFDNeMswr80IX0AGhiTS5f7Itmas6ee6jtoc&dib_tag=se&keywords=rv+ac+air+filter+cut+to+fit&qid=1752515341&sprefix=rv+air+filter+cut%2Caps%2C123&sr=8-11

Using a piece of the foam as a pattern, cut out new ones with scissors. It's poly material and I put mine in the washer on gentle cycle.

You've already had the epiphany that air flow is king, just keep searching for ways to improve it.

 

[Mikelff]

We have a 2017 3791RD. The 2 AC units are ducted together and cooling the front bedroom on 1 AC is all but impossible in hot weather. Sometimes while traveling we have limited power (30 amp) and for just a quick overnight we don’t need to cool the entire coach. It was 97 deg outside. And running 1 AC unit I can maybe get it down to 85 because half of the cold air is going to the kitchen and living room that we are not using while sleeping. Has anyone ever been successful in installing a baffle in the central duct system so cold air could be blocked off from the kitchen and be circulated in the bedroom ? Being that AC unit has its returns in the bedroom, it should circulate good. This way we could cool down the bedroom only at night. It takes a long time to cool such a big space it extreme heat. I think this could be a solution for a quick stop overnight on limited hook ups. If anyone has done this can you share how it was accomplished please?
As always. Thank you all. I enjoy reading all the posts.

While replacing your vents (I did this as well) take some of the A/C foil tape and make sure your vents are sealed where your vent hoses connect to the vent. This is an extremely common problem where there are large gaps or have come loose from the vents. Some threads I read said they found some not ever connected from the factory. If you have these gaps, a good amount of your A/C is going into your attic. I fount these vents that can be closed do increase air to your other rooms/vents. Be careful when opening and closing the vents as they are thin plastic and break easily.