Air Conditioning Mod.

[traveldawg]

By now I suppose many folks have seen that air conditioner foam thingy that Grand Design is supposedly putting in some Acs. You know - the expensive foam thingy that directs air flow into the ceiling ducting and eliminates the "dump" feature on the AC.

I had already done that - twice.

The first change I made months ago was to blocked off the dumping slats by putting a board with a foam backing on the bottom of the plenum where air flows into the ducting. And I turned the AC cover 90 degrees to more directly draw in air.


This is the blocked off air dump chamber. I just used some 1/8" luan board with some foam glued on it and screwed it into the AC flange.


I rotated the AC cover 90 degrees so one full set of vents was directly below the intake chamber.

Then I got to thinking if I could get the air to flow directly from the output of the AC's blower and into the ducting I could maybe reduce some turbulence. So I added some foam cut and carved at angles and put the in the plenum to help direct the airflow. And I added a pretty basic "diverter" to the board I was already using to block off the plenum so it doesn't dump directly. It's hard to see, but the foam is all cut at angles in the photo.


This the chamber before and after adding foam (it's hard to see the angles but they all slant to direct air from the blower more directly into the ducts). The third photo is of the cover I was using to block the plenum's dumping feature; it shows the "diverter" I put on it.

I think I get a bit more air flow but don't have any instruments to measure. I did move around some adjustable vent louvers from the bedroom into the living area to better re-direct air as I could tell I was getting a bit more air flow in the rear vents. I'm pretty satisfied with the mod.

The rig was already plenty cool. I just thought I could make the AC a bit more quiet by blocking off the dump vent and rotating the cover. I can't tell by ear if it is and quieter, but without the dump vents and blocking the plenum it think it must be. I think my next mod will be to change the intake in an attempt to reduce the noise a bit more.

[TheLexx]

By now I suppose many folks have seen that air conditioner foam thingy that Grand Design is supposedly putting in some Acs. You know - the expensive foam thingy that directs air flow into the ceiling ducting and eliminates the "dump" feature on the AC.

I had already done that.

First I had blocked off the dumping slats by blocking off the bottom of the chamber where air flows into the ducting. And I turned the AC cover 90 degrees to more directly draw in air. Here is what I did first....


This is the blocked off air dump chamber. I just used some 1/8" luan board with some foam glued on it and screwed it into the AC flange.


I rotated the AC cover 90 degrees so one full set of vents was directly below the intake chamber.

Then I got to thinking if I could get the air to flow directly from the output of the AC's blower and into the ducting; maybe reduce some turbulence. I tried different approaches and settled on some foam cut and carved at angles. And I added a pretty basic "diverter" to the board I used to block off the plenum so it doesn't dump directly. It's hard to see, but the foam is all cut at angles in the photo.


This the chamber before and after adding foam (it's hard to see the angles but they all slant to direct air from the blower more directly into the ducts. The third photo is the cover I used to block the chamber from dumping; I figured the piece of foam I added would help direct the air and maybe reduce some turbulence.

I considered just putting some foam to direct air out of the blower chamber directly into the ducts but realized with the crazy-eight kind of ducting that GS uses I probably need to allow the ducts to sort of cross-feed, so I went with the open chamber kind of arrangement.

I think I get a bit more air flow but don't have any instruments to measure. I did move around some adjustable vent louvers from the bedroom into the living area to better re-direct air. I'm pretty satisfied with the mod. The rig was already plenty cool. I just thought there was room for improvement.

I don't think the AC got an quieter but because I closed off one chamber I figure it has to be a bit more quiet; I just can't tell by ear that it changed much. That's what got me going on this - trying to quite down the AC a bit. My next mod will be to change the intake in an attempt to reduce the noise a bit more.

I'm a bit confused by the pics. Pic 4 shows the foam in place but there's a hole on the inferior surface allowing cold air to enter the dumps (should you choose to use them). But in the first picture you've got a piece of board block that.

Here's what I've seen folks do - they just use foam board and build a box to contain the cold air on its own side, totally separating it from the intake side.

[traveldawg]

I may have confused things.

At first I only had the board covering the plenum, thus blocking the dumps and I rotated the vent cover 90 degrees for more of direct air input. It was pretty much the same as others had done building a foam box. I did that some months ago.

Then recently I got to thinking that maybe I could do something to sort of direct the air straight to the ducts in the plenum to reduce any turbulance. That was the second mod to put some foam into the plenum to reduce any turbulence. Then I just covered it all up again with the board I used previously.

I edited my original post to see if I can clear that up.

[TheLexx]

I may have confused things.

At first I only had the board covering the plenum, thus blocking the dumps and I rotated the vent cover 90 degrees for more of direct air input. It was pretty much the same as others had done building a foam box. I did that some months ago.

Then recently I got to thinking that maybe I could do something to sort of direct the air straight to the ducts in the plenum to reduce any turbulance. That was the second mod to put some foam into the plenum to reduce any turbulence. Then I just covered it all up again with the board I used previously.

I edited my original post to see if I can clear that up.

OK I think I get it. It looks like in this pic #3 you've added thicker foam to extend the opening of the cold air exhaust to almost the level of the race track system ducting. That's what the hole is for. And then you added the diverter to block the mixing of the room temp and cold air.

Could it be that the cold and warm air are still mixing a bit? The other mods show the entire box totally sealed off from the room air intake? Just a thought.

[traveldawg]

I'm not sure why the folks who made that 2-sided box (the one in pink foam) needed a separator between the warm air intake and the cold air output That should already have been there.

You can see in my ACs divider in the first photo. It is a think foamy/fiber type separator. Since I took the photo looking straight up into the AC it is a bit hard to tell it's there. But you can see the foil tape I used when I initially got my rig to make sure that divider stayed in place and didn't leak. All the ACs like mine should have had that as part of the whole assembly. I could see if it was missing that it would be pretty problematic.

What is not shown in the photos is a piece I removed that both allows air intake from the vents when they are on the side as well as allow the dump vents to work. I removed that when I made the first change blocking off the cold air plenum.

Hopefully this clears things up a bit more.

Other style ACs (I'm not sure what GD is using now) may be different and not have that fiber/foamy separator necessitating the use of the box in the other person's mod (the 2-sided box).

[TheLexx]

What many folks have found is that OEM divider bar is often placed in the wrong place. Mine was positioned so that it allowed the room air intake to leak over to the cold air side. That greatly decreases the efficiency of the AC. I ended up opening up both AC units and then proceeded to tape that bar into the correct position.

I also took all the vent covers off and checked the fit of the vent into the racetrack system. What I found was in many of the vents, the foil tape that was used to seal the vent to the racetrack, was not truly sealed. In many areas the foil was sticking up, allowing the cool air to escape into the area between the duct and the luan. So I went ahead and taped down all the vents properly. The result of proper positioning of the divider bar and properly taping down all the vents, was dramatic. While I was unable to get the trailer down below 78 degrees on a 100 degree day, I am now able to cool it down to 72-74.

Grand Design apparently has adapted a new design mod for their AC units using a foam box from RVAirFlow.com. That pink box you see in the pics I posted, was an attempt by a FB Group member to create his own inexpensive version of that now OEM modification. By all accounts it works well. I have the foam board, but I have not tried it yet. The beauty of the mod is that it is easily reversible.

I'm not sure why the folks who made that 2-sided box (the one in pink foam) needed a separator between the warm air intake and the cold air output That should already have been there.

You can see in my ACs divider in the first photo. It is a think foamy/fiber type separator. Since I took the photo looking straight up into the AC it is a bit hard to tell it's there. But you can see the foil tape I used when I initially got my rig to make sure that divider stayed in place and didn't leak. All the ACs like mine should have had that as part of the whole assembly. I could see if it was missing that it would be pretty problematic.

What is not shown in the photos is a piece I removed that both allows air intake from the vents when they are on the side as well as allow the dump vents to work. I removed that when I made the first change blocking off the cold air plenum.

Hopefully this clears things up a bit more.

Other style ACs (I'm not sure what GD is using now) may be different and not have that fiber/foamy separator necessitating the use of the box in the other person's mod (the 2-sided box).

[frank4711]

I installed the RVAirFlow.com in the living area of our 2930 2 weeks ago, I was so happy with it I just put one in the bedroom yesterday. Install was simple and a obvious improvement in the volume of air being moved around the unit. This is our 3rd 5ver and we have never had a issue with the ac working I always had the feeling of cold/warm spots from lack of air movement. This upgrade I would guess produces a 30-40 % increase in air flow just on the low cool setting and may be a little quieter but I did not consider ours loud. While not a cheap upgrade it works and here in Fl where you end up in full sun at some state parks I really feel I got value for the money spent, a cool RV in a 95 degree FL summer is priceless. Set at 75 this weekend with temps at 93-95 and heat index at 110 the unit reached temp and shut off, we were partial sun/shade. For the DIY guy's I am sure you can build something similar with some effort. later Frank

[Double Eagle]

I installed the RVAirFlow.com in the living area of our 2930 2 weeks ago, I was so happy with it I just put one in the bedroom yesterday. Install was simple and a obvious improvement in the volume of air being moved around the unit. This is our 3rd 5ver and we have never had a issue with the ac working I always had the feeling of cold/warm spots from lack of air movement. This upgrade I would guess produces a 30-40 % increase in air flow just on the low cool setting and may be a little quieter but I did not consider ours loud. While not a cheap upgrade it works and here in Fl where you end up in full sun at some state parks I really feel I got value for the money spent, a cool RV in a 95 degree FL summer is priceless. Set at 75 this weekend with temps at 93-95 and heat index at 110 the unit reached temp and shut off, we were partial sun/shade. For the DIY guy's I am sure you can build something similar with some effort. later Frank

I have been contemplating putting the RV air flow in our bedroom A/C. We have one in the living room. Glad to see someone has done it and seen further improvement. I might have to bite the bullet and get one for the bedroom A/C.

[frank4711]

I have been contemplating putting the RV air flow in our bedroom A/C. We have one in the living room. Glad to see someone has done it and seen further improvement. I might have to bite the bullet and get one for the bedroom A/C.

The flow improvement in the bedroom is so good that I will not even consider any setting but Cool Low. later Frank

[cookinwitdiesel]

The flow improvement in the bedroom is so good that I will not even consider any setting but Cool Low. later Frank

Thanks for the quick review on the RVairFlow kit. I have been looking at that but not bit the bullet yet. I did just retape every AC vent and the 2 units since the factory job was pretty appalling. I do not think we are suffering from bad airflow, but we do have a lot of AC noise. I would love to get the noise down without impacting flow - I suspect it is on the input side as opening/closing the dumps does not make a big difference in the noise.