Testing The RV Airflow Systems Ducted Insert for a Coleman Mach 15 in an 2019 Isata 5

[BLT4SPD]

Here’s an interesting product review for you; the RV Air Flow Systems foam ducted insert for the Coleman Mach air conditioner units. I had read about this little guy a few months ago, but had a hard time getting it because it was consistently listed as out-of-stock and I ASSUME that was a result of COVID-19, but I didn’t ask. Regardless, they sent me an email a week or so ago and said “back in stock” and even provided a coupon code for a discount! Yay! Who doesn’t like discounts? During the ordering process, I was asked what Grand Design model I had…..uh, what? Yep, made for Grand Design and only Grand Design and you can’t complete your order until you tell them what Grand Design RV you have. The claim is that even though a Coleman Mach 15 is a standard unit, they simply can’t account for any/all differences that manufacturers may have built into the roof and/or plenum area of the Mach 15. Hmmmmm……I say “No Way!” and ordered it anyway. I’m dying to see what this thing can do and I’m not going to be deterred by a few fields on an order screen asking me what Grand Design RV I have!

What this thing does is changes the supply air side of the Mach 15 from a plenum style supply to a ducted style supply. The results are REPORTED to be much more air flow and much quieter. Don’t worry, pictures are coming, but first the disclaimers:

MOST IMPORTANTLY: I did this install of my own accord and with my own money at stake. I KNEW going in that it was NOT supposed to fit my rig, but I went ahead anyway and I did NOT tell the vendor what I was doing. I was promised no compensation for posting this and I am posting this without them knowing about it.

NEXT: I am not a scientist, nor do I have super sensitive laboratory tools. I have cheapy tools that I bought from Amazon and I consider them to be semi-accurate. They are better than nothing though….in my opinion.

LASTLY: you should know that this product removes the ability to use the “Air Shower” functionality. The “Air Shower” are the vertical slots at the ends of the trim plate that you can open with the slider. They almost render your ducted vents useless.

Okay, first, this is what the inside of the Coleman Mach 15 looks like. On the side where you can see the square opening, that is the “supply side”. Air enters this space from the roof (cooled air when you have the AC on) and is forced into the ducts via openings in either side of the plenum. The only thing that gets air into your ducts is the fact that it has nowhere else to go.




This is the RV Airflow Systems insert. It is going to go into that plenum space and fill it up. However, you can see how is move the air directly into your vents. It’s providing a direct path for the air to go.





They also provide these inserts that go into the sides of the plenum and further direct air into the ductwork. This is the ONE thing I had to modify to make it work for our Isata 5. They provided them with 3/4” foam tape as the sealing mechanism between the insert and the ductwork. That was simply too thick for me. I push….and wiggles and poke and prodded….I got out putty knives and everything I could think of to try and slip the foam block into the plenum and it simply would not work. So, I scraped off the 3/4” foam tape and replaced it with 1/4".



I also added some felt strips to the side that faces the foam block in the hope that it would be easier for it to “slide” up and in-between these duct inserts. I also felt like it might help with noise since the foam and these inserts are designed to touch each other.



This is what they look like in their final resting position.



This is what the foam module looks like in the plenum.



….and then with the Coleman bracket securing things in place.



….and finally, the Coleman cover in place (WIHTOUT the air shower plate installed).



.....and I am limited to 10 pictures per post, so keep scrolling for results.....

[BLT4SPD]

Of course, it’s really the results that we are looking for, right? Well, here it goes. I used a handheld decibel meter for the noise test. I put a piece of tape on the floor so I knew I was standing in the same place for both the ‘before’ and ‘after’ test. In both cases, I am standing directly below the AC unit and the AC is set to “High”. The Generator is running in both tests because I don’t currently have 50amp service at my house (working on it, but not yet). All windows, doors and vents in the RV were close. The ‘Before’ number is on the left and the ‘After’ number is on the right.




Air flow tests: I do not have a proper Balometer (flood hood type meter used in HVAC) and I am not going to go buy one due to cost. So, what I am using is a wind speed meter. In all cases I put my meter directly up to the air register in the roof and tried (by eyeball) to angle it at the same angle as the vanes in the register. Like I said, clearly not “scientific”, but since I used the same methodology in both the ‘Before’ and ‘After’, I’ll sleep okay knowing that it’s better data than just licking my finger. In all tests, I had all the registers in the bedroom closed and the single register in the bathroom closed. I only bought one of these foam inserts just to test it and therefore the rear AC unit has not been modified, so I closed those vents in the hopes that it would provide more realistic flow numbers to the ones that remained open. Again, in all pictures, the ‘Before’ is on the left and the ‘After’ is on the right. Just for reference purposes, this is what our floorplan looks like:



This is the driver’s side vent in the over-the-cab bunk area:



This is the passenger side vent in the over-the-cab bunk area:



Moving towards the AC unit, this would be the next one in line on the driver’s side. It’s just behind the cab:



Moving towards the AC unit, this would be the next one in line on the passenger’s side. It’s right at the coach door.



Moving back even more, this one is on the passenger’s side and just above the couch. It’s very near the fridge and has ALWAYS been a “problem child” of mine. You can see by the number that I do not get a lot of flow from this vent and I have no idea why.



This vent is on the driver’s side and in the kitchen:



This vent is on the passenger side, just behind the fridge:



This is the last vent I tested and it is on the driver’s side, right outside the bathroom door:

[BLT4SPD]

Here are the numbers represented as delta increases and increases as a percentage:



Bottom line; a 5.6db decrease in sound and average of 29% increase in flow. That’s pretty impressive.

Subjective test results: To my ears it was MUCH quieter than 5.6db. It seemed MUCH quieter, so I was really surprised that it was that low. If you were at a campground with hookups and didn’t have the generator running, that 5.6db decrease would be even more pronounced. I wouldn’t say that I could “feel” the extra flow from the vents. I could feel that they were moving more air, but I wouldn’t have guessed it was 29%. The “feel” that I did get was that it cooled off the inside of the coach quicker. I most certainly noticed that.

Time to order one up for the rear AC unit!

[rskeans]

Very good work and nice review.

[dannko]

Hey Ben, so it worked I see. Did you order for a specific Grand Design model, or any?

So all I would need is that 1/4" foam tape?

Also man that seems so expensive for a chunk of styro. but oh well.

Did you watch the video I sent you on the outside grill changeout to a screen? That seems like such a simple highly efficient fix, and with this could really turn the coach into a meat locker which it is now. Yet I like the noise reduction, that alone is worth it.

[TrailWayz]

Nice write-up and review. Really appreciate it.

I will have to put this on my to-do list.

If you could post the ordering link and Grand Design model you used that would be awesome.

[BLT4SPD]

Originally Posted by dannko

Hey Ben, so it worked I see. Did you order for a specific Grand Design model, or any?

I might have "suggested" that I had a 2019 Reflection 311BHS

Originally Posted by dannko

So all I would need is that 1/4" foam tape?

Yep. Truth me told, you could probably even take a razor/utility knife and cut down the foam they install. In the end, that might be easier and faster, but I had some 1/4" laying around so I used it. I bet that 1/2" would work even better. With the 1/4 I had a pretty easy time slipping the foam block in the plenum and it stayed in place without me holding it there, so that's good.....but I think it would have been nice to have a tad more resistance getting it in there for a tad better seal against those plastic duct inserts.

Originally Posted by dannko

Also man that seems so expensive for a chunk of styro. but oh well.

Yeah, not the cheapest thing in the world, but I couldn't engineer and produce it myself for anything less. The bigger surprise to me was the shipping cost; it was $25 for 1 and $50 for 2. My feathers always get a tad ruffled when shipping doubles because the qty doubles. Anyone who has shipped anything in their life knows that the cost shipping doesn't double just because the qty doubled and they are going to the same place.....but, oh well.

Originally Posted by dannko

Did you watch the video I sent you on the outside grill changeout to a screen? That seems like such a simple highly efficient fix, and with this could really turn the coach into a meat locker which it is now. Yet I like the noise reduction, that alone is worth it.

I must have missed it.....link?

[BLT4SPD]

Originally Posted by TrailWayz

Nice write-up and review. Really appreciate it.

I will have to put this on my to-do list.

If you could post the ordering link and Grand Design model you used that would be awesome.

Oh yeah, link....of course....I feel dumb for not including that. Direct link to the product in question:

https://rvairflow.com/product/mach-a...-mach-3-10-15/

Coupon code is: VIRTUAL10

the model I might have suggested that I owned was a 2019 Reflection 311BHS

[TrailWayz]

Thanks!

Boy, that's an early 2000's style e-commerce site. LOL

Really appreciate the thorough review, testing and install advice.

Even at a high margin of error your results are impressive for air flow and sound reduction. The cost is not that significant if they are running more efficiently.

Ordered two. Will install when I do the Micro-Air soft-starts in a couple of weeks.

For now, we adding heading down to the Long Beach RV Resort!

[dannko]

Ben, man I sent this to you somewhere, took me forever to find it, lol. I like this modification, I think it could work.

https://www.youtube.com/watch?v=aWUqQnEw-8Y

[bclemens]

Great write up...certainly something worth testing ourselves.

Though, it does eliminate the quick cool function which is nice at times, but not sure how often (other than RV shows) we actually use it.

[BLT4SPD]

Originally Posted by bclemens

Great write up...certainly something worth testing ourselves.

Interesting follow-up: I had a phone conversation with the president of RV Airflow Systems this weekend. He mentioned that they sent several of their kits to airxcel for testing and he is reporting that their product has now been certified by them and will not void the warranty of their air conditioners.

He also mentioned that they are going to be installed in all new Grand Designs.

Originally Posted by bclemens

Though, it does eliminate the quick cool function which is nice at times, but not sure how often (other than RV shows) we actually use it.

Yeah, I have my reservations about that too, but I'm going to save judgement until I see if the increased airflow out of the ceiling registers will accomplish the same goal.

[BLT4SPD]

Originally Posted by dannko

Ben, man I sent this to you somewhere, took me forever to find it, lol. I like this modification, I think it could work.

huh......that's pretty interesting. I may have to give that a shot. I love a little "shadetree" engineering sometimes.

[TrailWayz]

https://www.youtube.com/watch?time_c...ature=emb_logo

[nomad297]

EDIT:

I removed my original post about my question in the title of my post here and started a new thread so I wouldn’t hijack this thread.

Bruce

[nomad297]

Originally Posted by TrailWayz

Boy, that's an early 2000's style e-commerce site.

You sure got that right! I think, maybe, that site even got infected with the Y2K problem.

Bruce

[TrailWayz]

Couple of follow-on notes for my 2020 I5 30FW:

1.) I also replaced the weather strip on the duct inserts but for a different reason.

The duct opening is larger then the insert but the flange will cover it. I used the same 7/16" thick weather strip but replaced it with 3/4" wide so it would catch on all three sides. Otherwise, the insert just slipped into the opening instead of against the wall surrounding it. You want the inserts nice and snug against the foam block.

(the original weather strip is hot glued to the insert so it took a while to clean-up)

2.) I believe the I5 roof cavity is slightly shallower then the intended Grand Design so when I torqued the bottom bracket back in with 4 lag bolts to 45 in. lbs. spec it cut into the styrofoam block about an 1/8-3/16"

3.) I felt a little air escaping on the return side of the block, so I taped off all three return-side edges - top and both sides - with foil tape.

Observations: It is considerably quieter and you can feel the difference in airflow. It is noticeable on all accounts. Very pleased and easy upgrade.

Without changing the weather strip each unit should only take about 10 minutes.

[bclemens]

I have one sitting on my desk. I'll give it a test in my demo late July.

[Coda]

Wow! I’ll be giving this a go. 5.6 dB reductions is big when you realize every 10 dB change 2X in sound to our ears. I spent more money than that installing an upgraded sound system so I could hear over the AC units. Now I can’t hear my wife😁

[dannko]

Ben, we have the Mach 15 on our 35DB?