M2 Air Conditioning Airflow

[EdandShelley]

I’ve been working with Mike at rvairflowsystems.com to prototype a solution for our Atwood AirCommand. Just received and installed the prototype. Holy Cow! What an improvement in airflow and sound!

I didn’t have an anemometer so this will not be a Six Sigma analysis (inside joke from another thread post). But the approval and impression of my wife must be at least 7 or 8 sigma!
Seriously... The airflow improvement was very noticeable...we were able to turn off the rear AC and cool the RV with the front alone (albeit...we are in storage and not in the sun but it is 98 degrees in the warehouse).

Noise reduction was significant as well. Had a dB meter and measured 60dB prior to install and 52dB after install. That is awesome! No more air noise inside the ceiling box...now all we hear is the fan and roof compressor.

Mike said they are willing to move this to production if they can secure enough demand. He is going to speak with his manufacturer about offering a pre production discount to see if they can get the volume. More to come on that.

Here are the pics of my installation and some comments. Very easy...took about 20 minutes per unit to complete:

Atwood AirCommand


Main Insert and duct inserts


Remove cover(six caps and Phillips head screws)


Remove four corner bolts and take off the inside bracket


Remove foam separator (separates inflow from outflow areas)


Remove metal tape and clean up any excess adhesive from the foam separator.


Insert duct inserts. I had to increase the duct about 1” to the front. Very easy with a sharp knife. Then work to press all the metal tape down so that all is flush and has a 90 degree angle before inserting the inserts.



Insert the main deflector in place but leave to the front about two inches so you can start the mounting bracket bolts. Then you can simply slide it back into position before tightening the bolts.



The inside mounting bracket has a ~1” flange that sticks up and holds the new airflow system insert in place.


Reinstall the cover with six Phillips screws and caps.

[halla]

Awesome. I will order 2 as soon as they are available. I like the review you wrote up as well as the ones from the other A/C units they already make these for.

[EdandShelley]

Originally Posted by halla

Awesome. I will order 2 as soon as they are available. I like the review you wrote up as well as the ones from the other A/C units they already make these for.

Thanks. Have given Mike the link to this post. He will monitor the number of interests and let us know what he can do.

Just wish I would have come up with this idea. Very simple design and solves a problem/increases performance. Kind of investments I like to find.

[MoJoe1003]

I’m a prospect. Has he given you an approximate price at this point?

[EdandShelley]

Originally Posted by MoJoe1003

I’m a prospect. Has he given you an approximate price at this point?

Not yet. I asked him for the price and discount for pre production orders. Will post as soon as I hear from them.

[mookieblaylock]

I'm in for two as well. Nice write up!

[FarFromLiberal]

After that write up I’m definitely in the market for 2, thanks!

[bambamdrw]

Interested for my DX3. I've done significant taping to try and increase airflow. Currently it only draws air in through the first two rows in the filter.

[Graphicaccents]

Nice wright up, put me down for 2

[DX321go]

Following

[Happyatrest]

I would also be interested in these for my 2018 DX3.

Thanks for the great write-up and the installation pictures.

Joe

[Travler]

Interested also. Will be following.

[BellaBee]

All,
I just worked on my units today and achieved the same result for about $30.

I removed the shrouds and bought some insulation and silver HVAC ducting tape and significantly improved both flow and lowered the sound by at least a factor of 2 or 3. My dump vents are now non operational but you get that result from the kit as well.

What I found when I opened up my units (from the inside) was the piece that was supposed to be separating intake from output was not even installed correctly and there were no supports or tape to keep the two areas separated properly resulting in probably 20-30% of the cold air going right back into the return before it even had a chance to exit the system (e.g. took the path of least resistance).

So I completely sealed off the return (intake) from the exhaust (output). To get the fan noise down I effectively sealed off the lower dump channel from the exhaust by building up a level of insulation with some silver coating on the inside of the exhaust port. This worked perfectly. Our units are super quiet and the air pressure/volume coming from the roof ducting ports in substantially better.

Very happy and only took a little time, HVAC tape and insulation to achieve the same result for $30.00

I'll say I was very disappointed to find the inside of the units with insufficient taping to make this system work correctly. This is clearly an area the factory could improve on to ensure a good system is delivered with out unneeded noise level and inefficient HVAC operation.

Cheers,

[BellaBee]

Btw, this post did help me think about this situation and dive into the kit design and have a glance at my configuration to realize that while the gentleman who designed the add on plenum did a great job, it also showed me that I could also achieve the same result by just getting the existing design properly configured with the added change of eliminating the dump ports. This is the change that significantly reduces the noise level. Think of all that air and fan noise frequency impinging on the lower housing shroud with no place for that noise to go but in your coach.

PM me if you want any more details but it really was a very easy fix.
Cheers,

[EdandShelley]

Originally Posted by BellaBee

Btw, this post did help me think about this situation and dive into the kit design and have a glance at my configuration to realize that while the gentleman who designed the add on plenum did a great job, it also showed me that I could also achieve the same result by just getting the existing design properly configured with the added change of eliminating the dump ports. This is the change that significantly reduces the noise level. Think of all that air and fan noise frequency impinging on the lower housing shroud with no place for that noise to go but in your coach.

PM me if you want any more details but it really was a very easy fix.
Cheers,

BellaBee,
That is really good work and congratulations on solving the problem with innovation. After doing the prototype installation, you are right, it could potentially be accomplished with some duct work inside the plenum area.

For me... I like the engineered solution and design testing. Coleman has approved it for their AC units and Grand Design is now making it standard on their new RV's according to the company website. They also note that they are working with Dynamax.

Again great job... especially for $30. Don't know what the cost will be for the production unit but assume it will be similar to the Coleman units at around
$170. The R&D person that contacted me said they would potentially offer a pre production discount for any advanced orders. Expect to hear from him this or next week.

[johndjmix]

The only thing I don’t like about this is eliminating the dump ports. I use the dump ports almost exclusively. The air flow is so so so much better. When you go into the ducts you are going through areas heated by the sun, and restricting flow...which is, from what I understand, the entire reason the dump switch was put into the units.

Please elaborate.

—john

[BellaBee]

Before I did this fix to the units I would have agreed with you on only using the dump ports. That is what I used to do. Not any more.

My roof vents are much stronger now and the cold air is distributed more evenly around the coach cooling it down much quicker. There are a few of the vents that still seem to be weak when compared to others but I suspect that is a channel design issue or something is hindering the flow on those vents. I'll check that out next. With both units running the vents are really pushing out lots of air. I even have to close some of them a bit which I never did before now. Ironically, the vents nearest the units are the ones that have the weak flow...

My hypothesis is those vents are so close that the air flow heading into the main channels is hitting the perpendicular channel to the air flow and then heads mostly down the vent in force where the closer vents are at a 90 degree branch right after the T and the air current is moving right past them (mostly) so they end up with a lower bleed-off force (aka eddy currents) instead of proper flow. This is a channel design issue (if I'm correct). It may be fixable by a slight modification to the inside of the channel to bleed off some of the air. Haven't look that closely yet so at this point only a hypothesis...however the physics seem straight forward.

The trade off is mitigated by the proper flow AND more importantly the noise level is so significantly reduced we don't need to crank our living room TV volume to 100% to hear it clearly. Also, sleeping will be much nicer given the lower noise level.

Cheers,

[MoJoe1003]

BellaBee, can you post pictures of your $30 solution? I would love it if I could achieve results like you describe for $30 instead of potentially spending $170 per kit on the production ones.

[bclemens]

I like the white noise at night...so I also, sometimes open up the dump.

The other reason is the last stop we only had 15A hook up. So I ran just the Bedroom A/C so that room stayed nice and cold, one half of the quick cool open. So, some air went to the ducts, but most went to the bedroom.

90+ outside, stayed 71 inside.

[shultz01]

You can count me in. :-)