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Old 02-21-2021, 02:18 PM   #1
Windermere Campers
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Air Flow Issues

I have 2017 3950BR. We live in Florida and camp all year. During the summer the a/c has a difficult time keeping up. Per forum recommendations I have tried removing a/c vent covers to let a/c flow better. Helps but still not great. I have seen a lot of posts about crushed ducts. I checked that today. Nothing seems crushed. I have read numerous strings that inserting a 1 1/2 inch pvc pipe may help. Several questions:

1. Should I insert the pvc pipe into the vent or the return or both?

2. I bought some 1 1/2 inch pvc pipe but it is thick and non-flexible so how long a piece do you recommend inserting? My a/c vent only has a 3-4” diameter hole and my return in rectangular about 12x4? I only ask because my 1 1/2 pipe will not bend so I am limited on the length of pipe.

3. Do you insert the pipe at the opening or try to push in far into the vent?

4. Most stores sell schedule 40 pvc pipe. Should I be using that or something thinner.

5. If inserting pipe doesn’t work any other suggestions? Thanks in advance.
 
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Old 02-21-2021, 03:39 PM   #2
Golfmedik
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Originally Posted by Windermere Campers View Post
I have 2017 3950BR. We live in Florida and camp all year. During the summer the a/c has a difficult time keeping up. Per forum recommendations I have tried removing a/c vent covers to let a/c flow better. Helps but still not great. I have seen a lot of posts about crushed ducts. I checked that today. Nothing seems crushed. I have read numerous strings that inserting a 1 1/2 inch pvc pipe may help. Several questions:

1. Should I insert the pvc pipe into the vent or the return or both?

2. I bought some 1 1/2 inch pvc pipe but it is thick and non-flexible so how long a piece do you recommend inserting? My a/c vent only has a 3-4” diameter hole and my return in rectangular about 12x4? I only ask because my 1 1/2 pipe will not bend so I am limited on the length of pipe.

3. Do you insert the pipe at the opening or try to push in far into the vent?

4. Most stores sell schedule 40 pvc pipe. Should I be using that or something thinner.

5. If inserting pipe doesn’t work any other suggestions? Thanks in advance.
The vent "mod" required for the '16-'17 rigs is talking about putting 1 1/4" Inside diameter pipe in the return vents as the units could not breathe. The 1 1/4" has an outside diameter of 1 1/2" that equals what the duct size should be. Usually the opening size of the return vents are around 9" so I cut mine at 9" lengths and inserted them lengthwise to the rig and then turned them to point the direction of the airflow. That way the air flows through the pipes. I put one on either side of my ducting on one side but the other side was so severely crushed that I had to put three on that side as one went in the middle. Also, remember to do the front AC unit too! I then ordered JR Products vent covers/vents as they had larger openings for airflow, but you can always cut out every other directional vent on the cover to give you more flow.
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Old 02-21-2021, 07:48 PM   #3
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One more thing I did was to cut down the fixture that holds the vent covers so that it matched the height of the ductwork. Before that they proturded into the ductwork blocking some flow.
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Old 03-03-2021, 04:36 PM   #4
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Thanks for the reply. Can you send me the information for the JR Products vent covers?
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Old 03-03-2021, 05:54 PM   #5
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Cover your stair vents.
I always say don't cover them because they are the furnace air returns BUT, for the summer, cover them. Also get magnet vent covers for your floor air registers. Trap all the cool dehumidified air inside your cabin.
Just don't forget to take these all off if you have to run the furnace.
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Old 03-03-2021, 06:21 PM   #6
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I was going to wait until closer to the summer to share this but some of you could use this info now...
Window film test
I have frameless windows with dark tint.
The problem is, the sun heats the glass, the aluminum frame conducts the heat right through to the inside of the RV and the frame gets so hot you cant touch it.
Putting reflective window film on the inside, I believe, is not effective. You need something to reflect the heat away before it gets in. OR shade the window entirely (awnings being best solution).
I ordered one silver and one bronze (matches my color scheme) reflective interior cling window film. I wanted something removable so I could put it on in the summer, to keep the sun/heat out. Then remove it in the winter, to let the sun in to warm the RV.
I put the film on the outside of the glass to reflect the heat away. I put silver on the left window, bronze on the right side and shade the top right side to compare all four (silver, bronze, shade, full sun).
Note: the film is made for window INTERIOR not exterior. Not my best work, lots of bubbles, after all, this is just a test.
RV rear window is facing due west. Test was done at 3pm under full direct sun. Outside air temperature 88°F.
Area:
A= full direct sun
B= shade (white towel)
C= bronze reflective film
D= silver reflective film
Temperature measured on the window FRAME on the INSIDE of each area using a laser thermometer.
A= 130 °F
B= 99 °F
C= 107 °F
D= 105 °F

Not that much difference in temperature between bronze and silver. Bronze does go with our color scheme so we will go with that for all windows that do not have awnings. I guess we will wait and see how long this cling film lasts. I'll let you know...
Installed 9-5-20.
Bronze film came off 10-29-20. But, full disclosure, I did not trim off the excess film (zoom in on the bottom right corner and you can see how much was overhanging) so it flapped a lot going down the road and eventually came off.
The silver film which was trimmed to the window edge is still firmly attached (3-4-2021). I'm guessing the bronze would still be attached if I had trimmed it properly.
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Old 03-03-2021, 07:56 PM   #7
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I don't have any photos of the shades we put on but while in AZ two years ago we ran across a couple that make and install window shades/screens that snap onto the outside of the windows. They come in multiple colors so you can decide on the color you want to use. They are screens that have thin wire filament running through them and that filament captures and expels any heat the sun puts on them. It's dark out presently but will check out the name of the company/couple that makes them and post it on this post tomorrow or Friday. They really work and the Monte can sit out in the blazing hot summer sun and still remain cool inside with just the main living room A/C running.
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Old 03-10-2021, 05:00 PM   #8
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Originally Posted by Windermere Campers View Post
Thanks for the reply. Can you send me the information for the JR Products vent covers?
https://www.walmart.com/ip/JR-Produc...hite/198742002
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Old 03-10-2021, 07:26 PM   #9
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Originally Posted by Rondo View Post
I don't have any photos of the shades we put on but while in AZ two years ago we ran across a couple that make and install window shades/screens that snap onto the outside of the windows. They come in multiple colors so you can decide on the color you want to use. They are screens that have thin wire filament running through them and that filament captures and expels any heat the sun puts on them. It's dark out presently but will check out the name of the company/couple that makes them and post it on this post tomorrow or Friday. They really work and the Monte can sit out in the blazing hot summer sun and still remain cool inside with just the main living room A/C running.
We have them too. Windows and frames were so hot before you couldn't touch them. Shades were a total game changer. We can only run one AC on our generator. Before we put the shades on it didn't seem to do any good at all. Now we can walk the temperature down easily with just one AC running.

We wintered over in Quartzite this year. These guys were everywhere.

https://www.shadepro.net/product/window-cover/
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Old 03-28-2021, 09:37 AM   #10
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What make is the AC units?
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Old 03-29-2021, 06:08 PM   #11
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Dometic
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Old 03-29-2021, 08:11 PM   #12
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RVAirflow has a kit for the Dometic Brisk Air II. That is what I have.
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Old 05-12-2021, 08:35 PM   #13
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Air flow in the bonus room

Hey everyone. New on here....first post! Just picked up a 2019 Montana 385br. We loved the floor plan because of the bonus room. Took the couch out and put a crib for our 15 month old son! Just took it out for its first trip this week. Along the lines of people talking about windows getting hot, Ive noticed the same issue. Even with 2 A/C units its hard to get it cool. BUT bigger question is when our son takes a nap we close his door and actually put a towel under the door to keep the light out. With only 1 smaller vent on ceiling, the room gets way to hot. We noticed that the furnace (floor vents) gets plenty of heat at night in there so actually closed off 80% of the floor vent and that made the room pretty balanced with rest of the RV. As for A/C and cooling though, anyone have a recommendation for ways to pump more cold air in there?

Thanks!
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Old 05-12-2021, 08:52 PM   #14
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Hey everyone. New on here....first post! Just picked up a 2019 Montana 385br. We loved the floor plan because of the bonus room. Took the couch out and put a crib for our 15 month old son! Just took it out for its first trip this week. Along the lines of people talking about windows getting hot, Ive noticed the same issue. Even with 2 A/C units its hard to get it cool. BUT bigger question is when our son takes a nap we close his door and actually put a towel under the door to keep the light out. With only 1 smaller vent on ceiling, the room gets way to hot. We noticed that the furnace (floor vents) gets plenty of heat at night in there so actually closed off 80% of the floor vent and that made the room pretty balanced with rest of the RV. As for A/C and cooling though, anyone have a recommendation for ways to pump more cold air in there?

Thanks!

Bad idea to block the door. The a/c is a closed system, which means the air coming out of the vent, has to have a clear pathway back to the return. Closing the door and putting a towel under the door, will cause the ceiling vent's output drop to near zip, zero, nada. Same applies to your residential home system.
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Old 05-13-2021, 08:49 AM   #15
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As firestation12 says - DON'T BLOCK OFF THE RETURN SPACE UNDER THE DOOR! Don't worry, a baby will sleep even if a little light comes in under the door. As far as increasing AC air flow I suggest you like into installing a RVairflow devise in your AC system. If your 2 AC units are on a common duct install in both. Look up "RVairflow.com" for info.
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Old 05-13-2021, 11:18 AM   #16
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Bad idea to block the door. The a/c is a closed system, which means the air coming out of the vent, has to have a clear pathway back to the return. Closing the door and putting a towel under the door, will cause the ceiling vent's output drop to near zip, zero, nada. Same applies to your residential home system.
Yes totally agree with what you are saying. Except there are 2 vents cut in the side wall which basically just lets more air flow through the room. They are cut into the plumbing area under the bathroom. So the room isn’t starving for air, I made sure of that. Just wish I could add or “T” off a duct line to add another AC register. Thanks for the help. Will also look into RVairflow.com
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Old 05-13-2021, 12:55 PM   #17
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Welcome to the forum Aaron! I have a 3855 BR, which I think is the same layout. I work in the bonus room, and for it to get the best airflow from the AC vent, I have to have both AC's running. I think it's ducted to both, and keeping the door closed definitely cuts down on the flow rate as well.
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Old 05-14-2021, 10:01 AM   #18
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Yes totally agree with what you are saying. Except there are 2 vents cut in the side wall which basically just lets more air flow through the room. They are cut into the plumbing area under the bathroom. So the room isn’t starving for air, I made sure of that. Just wish I could add or “T” off a duct line to add another AC register. Thanks for the help. Will also look into RVairflow.com

I'm having trouble envisioning the return vents as you've described. I'm familiar with pass through vents through side walls as well as jump tubes over the top of residential walls leading to a hallway area ceiling opening, but I'm wondering how "cut into the plumbing area UNDER the bathroom" is accomplished? If you want to perform a visual test of your relief vent's effectiveness, tape a 12" length of toilet tissue to the ceiling a/c vent and note the difference in deflection with the a/c running with the door open and door closed + towels stuffed under. One thing you don't want to do, is vent any air flow to the basement area under the floor. That would create a negative pressure in the camper which would draw in exterior air. Glad to see young parents introducing their offspring to camping at an early age!
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Old 05-14-2021, 10:15 AM   #19
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Are the return vents under the plumbing area the furnace return vents? If that's the case, I don't think they would feed into the ducted AC system on the roof.
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Old 05-14-2021, 02:23 PM   #20
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Try this go outside on a hot day with a digital thermometer and take a reading on your sidewall particularly the darker colors then take a reading on your inside walls.
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