Seneca A/C Airflow mods

[Crossingover]

Originally Posted by 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.

You should have Coleman Mach 12 and/or 15 units. I have 2 15's on my 2016 and have the 'easy' button kit ready to install. May have fitment issue as the kit is for Grand Design fifth wheels where the ceiling thickness (plenum depth) or duct penetrations could be different than the Seneca. Surprisingly expensive but I understand that would be the case for an item such as this.

https://cdn.shopify.com/s/files/1/04...f?v=1593259112

[Rustynuts]

The pieces I designed to 3D print can easily be duplicated with the Owens Corning rigid pink or blue foam, I have made many things with it. With a sharp extendable utility knife, the kind with a snap off blade, you can quickly shave and shape this foam into any shape you wand and smooth it out with sandpaper and tape it in. A lot cheaper than buying something that doesn’t fit right and then cutting it up to fit.

[tpastorini]

Crossingover, let me know how it goes with the kit. I am interested to hear your install pain level and results.

Thanks to you and the group!!

Todd

[ks4936]

I used Rustynuts Thingiverse template for my 2019 Jayco Greyhawk with dual 11k BTU A/Cs. It worked perfectly. Here is a video of the install, https://youtu.be/dDhshzrS82Q

[RoWest]

Use CHANGINGLANES in the discount code for 15% off. $51 off for 2 units.
https://changinglanesrv.com/rv-airflow/

[lawingnutz]

On my 37K its important to keep the A/C air dump active. A/C vents are blocked by slide when its retracted. When traveling during hot summer months i run the A/C and without the air dump i am unable to cool the coach. Just something to be aware of.

[JohnH]

Printed the diverters and installed on both AC's. Results better than expected. During hot Florida's summer before the mod we would need both units on. Afterwards we only use the front unit. Net result better cooling and quieter sleeping at night. Great job on the STL files.

[Rustynuts]

Originally Posted by lawingnutz

On my 37K its important to keep the A/C air dump active. A/C vents are blocked by slide when its retracted. When traveling during hot summer months i run the A/C and without the air dump i am unable to cool the coach. Just something to be aware of.

IMO the slide doesnt cover the vents enough to hinder the cooling at all. We have the RB and it has the same large drivers slide as the K and with the slide closed it still cools great with no air dump. With this mod, you get so much more airflow out the vents the air dump is not needed.

[Rustynuts]

Originally Posted by JohnH

Printed the diverters and installed on both AC's. Results better than expected. During hot Florida's summer before the mod we would need both units on. Afterwards we only use the front unit. Net result better cooling and quieter sleeping at night. Great job on the STL files.

It is pretty shocking at the difference it makes, we never run more than one AC now.

[Semix-Hex]

This is what craftsmanship is like now. (Sideways of course).

I'll be making the parts out of foam board.

[Rustynuts]

Originally Posted by Semix-Hex

This is what craftsmanship is like now. (Sideways of course).

I'll be making the parts out of foam board.

Terrible isn’t it……

[Mikec557]

Originally Posted by Semix-Hex

This is what craftsmanship is like now. (Sideways of course).

I'll be making the parts out of foam board.

This employee must moonlight at the Keystone factory where my RV was built.

If you have a roof vent (bedroom maybe), pre wired for a second AC, you should investigate it. I pulled off the vent beauty ring. I found nice smooth metal tape over the race track vents. But after seeing the tape job on the vents at the AC I suspected poor workmanship under the smooth tape. I pulled off the tape. I was right. The ends of the HVAC vents were wide open. Untapped. My cold air was blowing into the attic space.

It might be worth taking a look.

[Bugzilla46310]

Originally Posted by Rustynuts

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!.

Been reading and looking at many of these videos. One item I have not seen stated, but am assuming, is that all of the vents are open when obtaining the before and after air flow readings. Is this a correct assumption? Have not seen actual dosimeter readings. The noise annoys me more than the airflow. Has anyone taken dosimeter readings? This may be a good spring time project for me. Wish I had a 3D printer!

[Rustynuts]

Originally Posted by Bugzilla46310

Been reading and looking at many of these videos. One item I have not seen stated, but am assuming, is that all of the vents are open when obtaining the before and after air flow readings. Is this a correct assumption? Have not seen actual dosimeter readings. The noise annoys me more than the airflow. Has anyone taken dosimeter readings? This may be a good spring time project for me. Wish I had a 3D printer!

I took all my air flow readings with all of the vents in the raceway open. There is a huge difference in the front and rear end vents, it would be nice if there was a cross over at the ends to even to flow out a bit more but I know where to stand if I’m hot

I have a decimeter on my phone, I didn’t take any readings before or after but it is definitely quieter. What’s nice is we get better cooling now by just running one AC unit so if we are in the front living area we run the rear one an if we are in the bedroom area we run the front one which makes it a lot quieter.

[Semix-Hex]

Originally Posted by Bugzilla46310

Been reading and looking at many of these videos. One item I have not seen stated, but am assuming, is that all of the vents are open when obtaining the before and after air flow readings. Is this a correct assumption? Have not seen actual dosimeter readings. The noise annoys me more than the airflow. Has anyone taken dosimeter readings? This may be a good spring time project for me. Wish I had a 3D printer!

I am very good with my hands and metal work. I'm not good with computers at all. I'm making my parts using sheet metal. I've seen them made with foam, cardboard, plastic and all sorts of stuff.

[Bugzilla46310]

Originally Posted by Semix-Hex

I am very good with my hands and metal work. I'm not good with computers at all. I'm making my parts using sheet metal. I've seen them made with foam, cardboard, plastic and all sorts of stuff.

Same here. If I had a 3D printer it may turn out worst than original! But it would be fun once I learned how to use it.

[Jmorenz]

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.

Hey RustyNUTS,

I like this modification a lot, one question, does your AC’s have heat pumps, I.e. heating elements? If not, what would need to be considered for those who do?

Thanks in advance.

[Rustynuts]

Originally Posted by Jmorenz

Hey RustyNUTS,

I like this modification a lot, one question, does your AC’s have heat pumps, I.e. heating elements? If not, what would need to be considered for those who do?

Thanks in advance.

I have 2 Mach 15 units both with Heat Pumps in them and I have installed the accessory heat strip in the rear unit. There really is no concern if you have them or not, all the work you are doing is on the outlet side. I used PLA for printing mine and neither the Heat Pump or the Heat Strip put out hot enough air to affect the pieces plus they have the foil tape over them for more protection.

[Jmorenz]

Thanks, I don’t have a 3d printer, put I have a fix in mind for that. One of the first things I plan on doing is opening up those units to see what is in store for me. We live on the east coast, and humidity bad out here, so AIR runs not stop in the summer.

Thanks for the reply. I will post my mod if needed….

John

[Rustynuts]

Originally Posted by Jmorenz

Thanks, I don’t have a 3d printer, put I have a fix in mind for that. One of the first things I plan on doing is opening up those units to see what is in store for me. We live on the east coast, and humidity bad out here, so AIR runs not stop in the summer.

Thanks for the reply. I will post my mod if needed….

John

If nothing else is done, just cleaning up the opening out to where it should be and cleanly taping it off for smooth air flow will help. Most of the pictures I have seen of the opening into the ducting, it looks like the worker just took his fingers and poked a hole in the foam and then taped it up. The air flow directional pieces can be made out of many simple material as many people have done.