Air conditioning/reverse Cycle

[Joey@HAT]

Can anyone give me advise on A/C units. The boat had what looks like a split unit. There is no duct work and not copper pipe. There is just he compressor in the engine room. I spoke to a surveyor who said use two self contained units. He said they are cheaper and easier to install. Anyone have one of these units???

 

[Tnstratofam]

I have worked on different types of HVAC units in houseboats as well as cabin cruisers. I've seen everything from small self contained units like they use on RV rooftops, split system air to air heat pumps, and self contained water source heat pumps ( usually located below deck.) What you're describing sounds like a water source. Some pictures of the unit in question would be helpful.

What is your question? Which is better? That all depends on your budget. It's usually cheaper to go back with what was there. Especially if it worked fine to begin with.

 

[JoLin]

I've had 2 boats with self-contained units, including the one in my Carver. I installed this one from scratch, all by myself. Not an easy job. It does sound as if you have something other than a self-contained unit. How about some info on your boat? How big is it, where are the vent registers located, and what area(s) are they supposed to cool?

As 'tnt' noted, it's usually cheaper to replicate whatever was in there originally, especially if you can salvage some of it.

 

[Joey@HAT]

Its a 41 Hatteras. Its an older boat. There is no registers the boat was remodeled in the early 80's The older split system was left in the bilge.I have been looking on different sites. Its seems to be the norm using the self contained units. I think putting in a split system would be a small fortune. If I put in a self contained unit. I could feed off it and supply one register to a stateroom and 2 registers in the salon. I would need to add a second system in the front bulk and supply the head a kitchen with registers. Then drill through the hull for water and out the side for the return.

 

[JoLin]

If you're planning to do this yourself, I'd suggest you read, read, read before you do anything else. I read the installation manuals from EVERY major manufacturer before I even put pen to paper to design my system. You may find that it makes more sense to install a new split system than to install 2 self-contained units. If you go with self contained, you'll likely need to double up on seacocks, strainers and pumps... or run the risk of insufficient water flow through the systems. That's critical, as is the the fact that all 3 components need to be installed below the waterline, with a constant 'upward' path from one to the next. The circulating pump is not self-priming and needs to be flooded naturally

Just saying there's a lot to consider, so do a lot of research before you decide on a system or spend any money. My little 9K btu unit cost me me over $3K all in, including a new, separate 30-amp circuit dedicated to the A/C..Took me about a month to do it. Be glad to help you out with any questions you might have. PM me f you like.

 

[gddavid]

I am a big fan of the self contained units, in my experience they are the most energy efficient and provide the least obtrusive installation. They do require the most expertise to install but done right they are quiet and have a good life. Where they seem so struggle are with relatively lighter boats with a lot of hull out of the water when running, as mentioned by JoLin, the pumps are not self priming and if the seacock is not placed properly, they can slurp just enough air to interrupt water flow. This shouldn't be an issue with a 41' Hatteras, which doesn't exactly bounce across waves. If you can place the unit outside of the engine room it will be a bit more efficient as the ductwork insulation isn't fighting against the engine room heat. I lived on a sportfish that had one unit located in cabinetry in the salon and another unit in the master stateroom's hanging locker, it was a great set up and kept the cabin comfortable and dry.

 

[JoLin]

If you can place the unit outside of the engine room it will be a bit more efficient as the ductwork insulation isn't fighting against the engine room heat.

It's not an 'if' question. It's a MUST that a self contained unit be placed in an area that is completely isolated from the bilge. If you don't do that, the unit will draw its return air from the bilge (path of least resistance), including all odors and potentially worse stuff like carbon monoxide. There's also the matter of the main unit's electrical connections/components not being inherently safe (spark protected). I spent hours completely isolating my dinette seat compartment so that the unit I installed in it could ONLY draw return air from the return register I installed.

Finding an appropriate spot to house the main unit is the least of it. You have to allow for electricity in, cooling water in, clean air in, air circulation around the chassis, (cooled) air out via ductwork, cooling water out, condensate water out. Every one of those has to be set up properly or you end up with a crappy system. And don't forget about the loss of usable storage space and servicability of the unit once it's in place. I started with 6 possible places to mount it. I eliminated them one by one as I considered how I'd address all the other things it needed. Ended up under the rear dinette seat and it worked out well, but it took weeks to plan the install, and weeks more to execute it.

My .02