Seneca A/C Airflow mods

[Rustynuts]

Originally Posted by rodpod

Thanks so much. I'll start this right away. in you pic on the 9th one down or next to last, it looks like you taped over an opening or something why is that?

This seals off between the intake and exhaust sides of the unit. When you take yours apart you will see and remove the factory divider. When you assemble your covers after the mods are complete you will not install the inner plastic roof panel. This gives you more of an intake area and you don’t need to divert any air to the sliding air dump vents on the cover. You do lose the air dump vents on the cover itself but you gain much more air flow through the ceiling vents. If you watch this video you will see this better.

https://www.youtube.com/watch?v=V9rE...ature=youtu.be

[rodpod]

Got it, thanks. I am looking forward to this project. Just another mod, one of many.

[Rustynuts]

The files I designed for that fit my unit are downloadable on Thingiverse now. They should fit any Mach 15 but just be aware there can be some small differences in every installation.


https://www.thingiverse.com/thing:4662142

[lslblues]

Originally Posted by Rustynuts

How did the upper pieces fit on your unit? How did you print the center piece, I printed it standing up on one end.



I also though about that. In Fusion 360 I can easily scale the triangle diverter down and to stick in the back of the duct where the air blows in but with the air flow readings Im getting, Im not sure it is needed. I may give it a try. I have got some rubber door stops to try sticking up in the 4 vents that are showing low flow. I checked for any obstructions and the duct is clear, I just think the air is moving so fast now and these 4 vents are so close to the blower. These door stops supposedly help direct some of the air out the vent. Worth a try, its all an experiment.

Did the door stops help?

[Rustynuts]

Originally Posted by lslblues

Did the door stops help?

Just got them today, haven’t had a chance to try them yet

[xoft]

Seeing these results got me motivated today! I don't have a 3D printer, but I am pretty handy with shears! I had some aluminum laying around. So I started with a cardboard template then Transferred that to the aluminum. The entire project only took an hour and a half! What a difference this makes in the vent output!! Huge!! Thanks for the direction! I love this site!!
T

[Bruceter]

Originally Posted by xoft

Seeing these results got me motivated today! I don't have a 3D printer, but I am pretty handy with shears! I had some aluminum laying around. So I started with a cardboard template then Transferred that to the aluminum. The entire project only took an hour and a half! What a difference this makes in the vent output!! Huge!! Thanks for the direction! I love this site!!
T

Nice job! I don’t have a 3D printer either. So what you have done is what I was thinking of when the time comes to do it? Thanks for sharing.

Also thanks to Rustynuts for bring this modification to our attention. It’s something I wouldn’t have given much thought to.

Thanks guys!
Bruce

[lslblues]

What are the height/width of that main duct on each side?

[Rustynuts]

Originally Posted by lslblues

What are the height/width of that main duct on each side?

On mine, the opening in the roof aluminum frame was about 2.75” x 7” and the opening of the actual ductwork was about 2.25”x 7” I used the foiled tape to make a smooth transition between them.

[Oma/opa]

looks like I have all winter to work on the mods. will probably be a good thing as our first outing next year will be going south from Ohio and will be putting it to the test

[lslblues]

Very interesting results for me. I saw a large improvement by improving weatherstripping and sealing divider board. I then ran 3 tests
1. Just added sound deadening material over air dump vent so all air was going out ducts
2. Added dividers but didn't have closed vent all the way to ductwork
3. Fully enclosed so I had the triangle piece dividing air into 2 enclosed ducts going to RV ducts out to vents

Saw very very little improvement from 1 to 2 to 3. Maybe 5% from 1 to 3. These units pump out 300+ CFM and my theory is that a 2.5X7 inch duct just can't move close to that amount of air. I tore everything out and am using dump vents again. Yes my vent flow is less, but feel like overall airflow is greater. My airflow from my vents isn't that much less even with air dump vents open.

Thanks Rustynuts for the great 3D designs though. I am printing your RV utility hatch cover as I type this.

[rodpod]

Originally Posted by Rustynuts

After seeing a YouTube video of a new product from RVAirflow to improve the AC/Heat Pump efficiency, I opened mine up on our Seneca and was shocked (well not really) at the the quality of the factory installation. The factory cutouts into the duct work looked like somebody just poked their hand through the foam and then taped it off sloppily. So I removed all the old crappy tape, cut foam inserts to fill the voids, cut out the foam into the ductwork clean and square and taped everything up. Then I 3D printed some pieces to tape in to create smooth clean transitions for air flow similar to what the $170 foam insert from RVAirflow does. Got everything taped in place and sealed off the air outlet side. I also eliminated the inner air dump panel as all the air is now directed into the ductwork and this leave more area for air intake. I took readings from every duct with an anemometer before I started and after. Every duct saw an increase of at least 1.5 mph airflow with the ends of the duct runs at the front and back of the coach seeing the most, the 2 front ducts saw an increase from 5.1 mph to 11.6 mph airflow! Quite a noticeable difference and well worth the time. This was just with one AC unit running, a bonus is the AC unit is quieter as the fan area is boxes off and insulated now. Most of this work is not Seneca related and could be done on any RV with ceiling duct work, I highly suggest you at least check the tape job and clean up the cutout to the duct work. The pieces I 3D printed for air flow could easily be formed out of some sheet metal or carved out of foam. The key is to reduce the turbulence and make the air flow more efficient. I opened up the rear AC and it looked the same as the front so I am also doing that one. This should make a huge difference in the summer heat.

I 3d printed the parts and just finished installing them in the unit. They dramatically improved the airflow over all. I have 2 vents that i am going to install the door stop deflectors in the vents to boost the flow. As a side benefit it quieted down the noise from the unit even on the highest setting

[Route 66 Traveler]

This weekend is my first experience with my AC after installing the RVAirflow insert in my Coleman Mach 15k unit.

We are camping in Quartzsite, AZ and the outside Temp is 84 degrees and inside the RV is a comfortable 73 degrees. The biggest change I noticed besides the increased air flow is that once the AC turns on it only has to run a few minutes before it reaches it's set temp and shuts off. It used to run almost constantly trying to keep things cool

It doubled the amount of air coming out of the ceiling vents. Before the mod I measured 8-9 mph wind speed with my digital wind gauge; after the mod all vents were showing 19-20 mph!

Well worth the cost in my opinion. Now no need to add a second AC.

[repeach]

My neighbor had some pink foam insulation laying around and he gave it to me. I thought I would try the triangle diverter. Only had enough to do the front AC. I WILL do the back. The amount of air coming out of the vents feels like I have both units on when only the front one is on. Nothing scientific but I would say the amount of air coming out has doubled.

[Rustynuts]

Originally Posted by rpietsch

My neighbor had some pink foam insulation laying around and he gave it to me. I thought I would try the triangle diverter. Only had enough to do the front AC. I WILL do the back. The amount of air coming out of the vents feels like I have both units on when only the front one is on. Nothing scientific but I would say the amount of air coming out has doubled.

A lot of people are doing it just the same as you did with great results, anything you can do to smooth out the airflow helps.



An update on mine using the 3D printed parts I designed, these mods work extremely well. We were in 95-100 degree weather last week, coach in full sun all day and we were only running one AC on auto the set at 66 degrees and it has maintained that temp with no problem all week. We have the overhead bunk curtain closed and a blanket sealing the cab off.



While traveling in 112° heat, we pulled into a rest area for lunch and to let the tires cool down a bit. When we stopped, the living area was 99°. We fired up the genny and turned both AC's on to hi cool and it was down to 71° within 1/2 an hour.

[pconroy]

Originally Posted by Rustynuts

An update on mine using the 3D printed parts I designed, these mods work extremely well.

I printed yours up and am grateful!

[repeach]

Originally Posted by Rustynuts

I have got some rubber door stops to try sticking up in the 4 vents that are showing low flow.

My neighbor to the north had some foam insulation too, so I went ahead and did the back unit.
The two vents right next to the back unit seems to be not putting out any air unless the front unit is on.

Did these door stoppers work?

[rodpod]

Originally Posted by rpietsch

My neighbor to the north had some foam insulation too, so I went ahead and did the back unit.
The two vents right next to the back unit seems to be not putting out any air unless the front unit is on.

Did these door stoppers work?

I have used both the rubber stoppers and a method my dealer used when i complained about poor flow from the vents. The round rubber door stoppers work where there is decent airflow from the vents. They actually increase the flow a bit. If you have almost no downward flow try this. Pull the vent cover off, place a piece of cardboard about 1/1/2 " high cut in a semi circle toward the back of the vent opposite the flow acting as a deflector to direct the flow downward. keep the height of the deflector low so that you don't block the all the flow to down stream vents. This along with Rusty's nifty 3d solution keeps my unit cool on the hottest days with one 15K btu unit.

[tpastorini]

I don't have a 3D printer and may just look to the 'easy' button and buy the kit from RV Airflow for my 2014 Seneca. The manual says that the AC is from RV comfort, I am reading on here that it may be a Coleman Mach unit. Can anyone with a Seneca help confirm what I have? Coach is in storage.

[Gunfighter]

Originally Posted by rpietsch

My neighbor had some pink foam insulation laying around and he gave it to me. I thought I would try the triangle diverter. Only had enough to do the front AC. I WILL do the back. The amount of air coming out of the vents feels like I have both units on when only the front one is on. Nothing scientific but I would say the amount of air coming out has doubled.

I do not have a 3D printer and I am dangerous around sheet metal. I went with the sheets of foam insulation. I used two YouTube videos for ideas and a guide. Wasn't that hard and greatly improved the airflow. First video was on a trailer but was for a Coleman Mach I.

https://www.youtube.com/watch?v=3Vhv_b-1zAk&t=1489s

https://www.youtube.com/watch?v=_BWQyXGowwY&t=302s

Not difficult at all and will greatly improve your airflow.