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Portuguese 03-26-2016 12:00 PM

Ceiling AC units
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The temperatures are very high down in the tropics. The heat is on and it gets very uncomfortable in the saloon without AC by day. I only have AC in the cabins.
I was wondering if a carefully installed Bus ceiling AC unit like the one below, would solve the problem while underway. I could use some power from my main to run it while saving time on genset.

Can that be done?


bilge53 03-26-2016 12:27 PM

I had one (not current boat) and it really did work well at the dock. Only needs 120V (no water) and a hole through the ceiling...a big hole. Down side is that depending on location of unit and the fly bridge helm when underway it will throw off a lot of heat making it real uncomfortable for anyone nearby.

Panhandler 03-26-2016 01:22 PM

We just bought a boat with one in the ceiling. Worked well for the sea trial... They can make sense if you're willing to cut the hole and install correctly.

Graycenphil 03-26-2016 01:27 PM

Where will you get the 120 volts, if the generator isn't running? Big inverter?

Portuguese 03-26-2016 02:39 PM

The one above is 12V.... I guess.
It connects to the main engine. Like a car!

bilge53 03-26-2016 03:14 PM

So it will use an engine driven compressor? This means you will have to route plumbing to it.

Portuguese 03-26-2016 04:27 PM

Yeap!. My questions are:
Does the length of hoses makes a difference in the quality of the final product?
Where the radiator goes?
What is the maximum distance of the radiator?
These are my doubts.
Obviously that if you ask to a dealer, he will tell you that all is possible and efficient.

bilge53 03-26-2016 05:39 PM

All of those things will have a bearing on the install and efficiency. There will not be a radiator as in an automotive install. I would contact the manufacturer not the dealer. I would also ask for references from someone who actually uses that brand.

Graycenphil 03-26-2016 09:39 PM

Do you have a link to that unit, or a brand name? It looks interesting, but sounds like a rather complex thing to install.

cmgreeniv 03-26-2016 11:59 PM

I think you would be better to just put a normal 120VAC one in that runs from your generator. Another option, I have a 12VDC one in my little boat, a 30 foot sport craft. It only does the front cabin, and will drop it down in about 30 minutes to a cool 75 with no humidity when its 100 outside, and the cabin is not well sealed. We looked at RV type units, but the major issue i found through hours of research and talking to folks who had them, was neverending rust lines from the units! They are not designed for boats, and after a year, they leach red rust at times of heavy rain. The unit you pictured, it a lemo/bus type unit, which requires a huge compressor on your main. I burn about 35 amps DC when running my unit, 32 for the AC, and 3 for the pump. So our 90 amp alternator is loaded up pretty good with the AC on, but it was not worth keeping the weight and support of a generator since we only run the AC when we are out fishing all day anyway, and the volvo diesel never gets turned off. For your salon, you would need at least 2 of these small 12VDC AC units, so you would be pulling down say 70 plus amps including the pumps. Thats ALOT of alternator belts to sustain that level of amperage. Stick with traditional 120VAC AC units and never look back. If you really want to look at one of those bus units, then i would say just design your own system with an engine mounted AC unit, and keel cooled heat exchanger.

FF 03-27-2016 07:02 AM

On our bus conversion the engine and AC pump are in the rear , the cold air is at the dash , so 35+ ft of piping is no hassle.

A delight is that an engine driven unit will operate at most any engine speed , so no thought like a belted cruise generator would require is needed .

You might contemplate a std RV rooftop unit $500-600 to purchase and far easier install.

They do operate with a sine wave inverter (not cheap) and large alternator.

The Delco DN 50 would be a wise investment as they can put out massive DV on an almost forever basis.

Probably 3 belts will be required to drive it , but running a belt for the AC compressor will also require a special set of brackets.

Shoalwaters 03-27-2016 07:46 AM

Fernando: sounds like your existing generator may be the best source of power. Can you modify the ducting of the cabin a/c's so it/they blow into the wheelhouse when required? 4" PVC pipe hidden in a varnished wooden trunking can solve many ducting problems.

folivier 03-27-2016 08:19 AM

Or you could buy a portable 120vac unit and move it around where you need it most.
Assuming these are available down south. Or a split unit a/c?
Arctic King WPPH-10CR5 10,000-BTU Portable Air Conditioner, White -

Graycenphil 03-27-2016 10:42 AM

Interesting. I never knew there were 12 volt (and 24 volt) ac systems. This company seems to have a good quality item, at least from their description:

They draw 40 amps or so, which is managable from an alternator. Lots of cars have 140 amp alternators these days, so it shouldn't be too hard to do with the boat engine.

FF 03-27-2016 02:49 PM

"They draw 40 amps or so"

Which may be 2000BTU or so.

An RV rooftop is 13,000 to 15,000 BTU and might do a better job.Engine driven might be 20,000BTU.

RV will also work in port at the power pole.

Most RV units are 100-140lbs , install for a 3G load .

The RV units mount in a 14x14 cut out that could be used with a fantastic rooftop fan unit .
Or most any RV item , all 14x14 .

healhustler 03-27-2016 04:20 PM


Originally Posted by folivier (Post 427737)
Or you could buy a portable 120vac unit and move it around where you need it most.
Assuming these are available down south. Or a split unit a/c?
Arctic King WPPH-10CR5 10,000-BTU Portable Air Conditioner, White -

Yeah, there's plenty of portable units down here, but being air-to-air, they aren't as efficient and, in my opinion, are over rated for BTU's. I've had several 8000 and 9000 BTU models that can barely do my stateroom. I figured I could throw one of these 10 or 12K's units under my helm and duct it through the problem, but there's too much glass. The 9K I left all day in the closed up 8 X 12 pilothouse couldn't keep up. A worthwhile addition would be 3M's UV blocking window film, which cuts heat transmission by something like 90 percent, according to the sales rep. Several new Krogens went with this stuff and it works so well that no additional pilothouse A/C was needed. Not cheap, though.

Graycenphil 03-27-2016 06:23 PM

The website claims the 12 volt unit is 8,000 BTU; can't say if that's accurate.

It sounds like you have a lot of options, but I kind of like putting film on the windows and ducting the cabin air to the pilothouse.

jeffnick 03-27-2016 08:51 PM

Don't shortchange the RV units - they are relatively cheap and hold up in salt environment. I installed one on a Parker that's going strong after 8 years.

Miy rooftop is on a 40 year old houseboat and who knows when it was installed?
One More Time Around: Boat Air Conditioning Improvment

The R2D2 units (portables) are only spot coolers unless they are dual hose - the single hose units draw in the ambient air for cooling the compressor and send it out the window. This air has to be sucked back in from somewhere. The hoses are terribly awkward and the unit itself needs to be secured...nice for rolling around the house but we found way too much trouble on a moving vehicle (we tried it in the van and on the houseboat).

And even a cheap window unit can be of use...
One More Time Around: Boat Air Conditioning

Graycenphil 03-27-2016 09:36 PM

Do you run that rooftop RV unit with the Honda EU2000?

jeffnick 03-27-2016 10:00 PM


Originally Posted by Graycenphil (Post 427972)
Do you run that rooftop RV unit with the Honda EU2000?

Yup. The 2000i does just fine running the 9,200 BTU Polar Cub.

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