No rooftop AC. What am I going to find?

dpearson

2011 Serenity
Hi all

I purchased a 2011 LTV Serenity late last year. One of the interesting things about it is that there is no rooftop AC. I am looking to install a Kingtec 12-Volt rooftop unit, but I am a little hesitant to just start cutting. If it had factory AC it would have been ducted. If I cut into the roof am I going to find ducts? If there is ductwork, then it becomes a little more critical where I put things. I can't imagine too many people will have done this installation, but I thought I would pose the question in case anyone knew.

Thanks
David
 

hoosierrun

Active member
Does your rig have the inside grills? My 2016 has 5 larger outlet grills and 2 smaller ones. It has 2 filtered return grills. For this project, you may want to see if LTV has a layout with placement dimensions and duct size/routing. It could be a big project to make it like OEM.
 

dpearson

2011 Serenity
Unfortunately, there are no vents and only minimal clues on the inside. I think the 2016 has a different roof molding that raises the AC a little bit. My 2011 has a fairly deep recess in the roof for the AC and a corresponding bump on the inside. I have included a couple of pictures in case it helps. One of the pictures is with the inside AC cover pulled down a bit from the ceiling. It is really hard to tell what you are looking at through the thin crack, but it looks like I am seeing the fiberglass of the roof. If that is the case, there are not likely to be ducts. But it raises the question of where the ducts would fit in a factory install. There was a good posting from a couple of years ago that shows replacing an existing air conditioner and dealing with the ducts. Not many pictures but a couple that show the ductwork. It appears that the ducts fit between the roof and the inside cover. I would have thought that there wasn't space to do that, but maybe the duct is thinner that I first thought.

I just wandered out to the RV to take a closer look and I think I understand. The ductwork would normally fit between the fiberglass roof and the inner cover. There is about 2" vertical space with the cover in place. This means that my unit does not have ductwork. It also means that I will need a plenum to fill the gap between the roof and the inner cover.
 

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israndy

2007 LTV Serenity
If you go up on your roof you will see a line in the fiberglass. That is the duct, it's about 7 inches wide and runs up to the skylight.

That is batty that your RV didn't come with an AC unit. I would have never believed you if you hadn't posted photos.

If you go up on the roof and look in the recess is it cut out at all or is it just the original flat molded fiberglass?

Even if you do decide it's worth it to cut the roof to install the AC you may find that there isn't power run to that location on yours as the original order declined to install AC. I do see some wires in your photo that may be what you need, but w/o it previously being installed you will need to remove that entire cover, which requires taking the shower apart. No fun.

Now if you are looking to install something OTHER than the default AC (Dometic Penguin) you will likely find that you don't have enough space in the recess to actually fit the other AC. And if you are looking for cooling on 12v, one option I would consider is a swamp cooler.



But then I live out west, we don't have that pesky humidity that easterners suffer.
 

dpearson

2011 Serenity
Interesting. Thanks for the insight. I have attached a picture of the roof. You can definitely see the line you mentioned for the duct. I can't see it from the inside, so I don't know if the duct metalwork is there. Even if there is something in the trough, there isn't any metalwork under the AC platform, so I think I will need to go non-ducted. FYI, you can also see in the picture that there are no holes in the roof. It is just a flat piece of fiberglass.

With respect to wiring, there is 120V power to the cavity for the AC. It would be tempting to go with a 120V unit, but I am going to try my hand at 12V with a Kingtec unit that I already have. It means I need to run some much heavier wires to handle the current. The Kingtec draws 45A at 12VDC.

As per your comment on fit, I am going to have to deal with the fact that the Kingtec is 30" wide and the recess is only 26" at the base. The recess widens out fairly quickly, so I think I can fit the AC if I raise it up about 1.5". It is a low profile AC, so it will still be shorter than the factory unit.

I think I am almost done with the research phase of this project. I'm going to have to cut a hole in the roof some time. I'm trying to build up confidence that I won't run into too much trouble.
 

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israndy

2007 LTV Serenity
Nice photos. Very interesting. What is going on with the paint on your roof? I see the side panels and the end are painted, but the roof where the AC will go and under the solar panels seems to be primer only. Nice solar install btw. Is that wire going into the side panel on the right the power wire from the solar or is that where your antenna goes in on your generation?
 

dpearson

2011 Serenity
I'm not sure about the paint on the roof. I thought it was just dirty. I bought the rig with the solar already installed, so I can't tell if it is factory or something else. The wire on the right is for the antenna. The wires for the solar panels go through the roof just beside the left solar panel. It is visible in the picture if you look closely. I've uploaded a zoomed in image for greater clarity.
 

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israndy

2007 LTV Serenity
Not factory. I imagine it would be difficult to keep that sealed, but at least it's out of the sun and wind for the most part. My Serenity was always so new I never thought I would need to think about sealing anything but the fans, then I got damage on the bottom of my front and rear cabinets, so don't forget to caulk the lines on the front and rear sections. I just did a LARGE stripe almost 2" wide to be sure. Just on the top.
 
David,
I'd suggest contacting the factory. They keep the fiberglass panel molds for all model years going back 10 years or more. Send them any questions you may have along with the VIN. You might learn why your Serenity was built without AC. They could offer suggestions on an AC retrofit. Willie Neufeld is one of their technical people who's been most helpful. He's sent me copies of wiring diagrams, schematics, and other model-specific details in the past. Mine's a 2012. Good luck. WNeufeld@tripleerv.com
--Mark
 

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