Air replacement.

A split should have only 2 connections (freon), At the air handler and at the compressor that are both braised and that's it. On a split system the only raw water connections are on the compressor units which usually are all mounted next to each other, and easy to see.....The chilled water has connections at every unit as well as bleed valves. Could also leak at one of the circulation pumps, shut off valves to them, connections, unions, etc. etc. etc. It's just a very over complicated system for a yacht under 75' and the only thing you seem to gain is a lack of compressor noise......they also never seem to cool as well (BTU for BTU) as compressor units. The chillers draw lots of amps and tend to short cycle etc. etc.

Yeah, of course I look for them. But, most of the boats I've been involved with only leak a little.....like adding 10 psi of water every 2-6 months or so. Some of them you can find the leak, some of them you never do. A lot of the connections are in places you cannot even get to, AND wrapped with insulation around them, so the leak might be at a connection to the unit, but leak out 20' away in a bilge somewhere. To add water you just open the freshwater valve that's permanently attached. I only add coolant if dropping the coolant every couple of years for maintanence, otherwise, you'd have to drop all of the coolant, add coolant with a pump and then water.....

The air temperature coming out of the vents of a package unit or split unit is generally 34F-48F. Usually low 40's. The water temp for a chilled water loop is usually 46-48F when it leaves the chiller, it only gets warmer the further you go. So, The air temperature coming out of a air handler for a chilled water system generally is 55-60F, from what I've seen and even as high as 68F towards the end of the loop, so there's a huge difference in the air temperature coming directly out of the vents. Also, all of the yachts I've run with chillers, NEVER max out the capability of the chiller, it is always cycling even if all units are demanding cooling at the same time and on full fan speed. I ran one yacht with two 3 ton chillers and it would max out the one but the second chiller would always cycle a ton. The further away from the chiller you get, the warmer the water in the chilled water loop gets as well, especially if a large unit before it (usually salon) or a lot of units are taking cooling capacity out of the loop water.

You get on a boat that's 90F and turn on all the package units or split systems on and they're blowing 34-46F air out of the vents within seconds and the boats instantly cooling. Do the same in a chilled water boat and it takes about 20 minutes just for the chiller to get the loop temp and all of the insulation down to temperature and even then the air coming out of the vents isn't ice cold. One of the boats I manage is a 2013 and blew the dock shorepower, boat was 93F inside and with all a/cs on the salon was only down to 91F, 30 minutes later.

I've managed and run yachts with all of the systems for over 13 years now, and spend about 150-180 days a year on and sleeping on all these different yachts with the various systems.

You can still have a total failure with 2 chillers, circulating pump going bad, flow sensor on chillers going bad, leak in the chilled water line somewhere, etc. etc.

All of the yachts I run 50-75' have at least 2 seperate units for the salon and most have 3, if 1 goes down it's liveable, and about the only thing that would make all go down is the raw water pump, which would kill a boat with chillers also.

You're seeing a chilled water system on some boats under 75' because it's cheaper to install, and the air handlers are smaller, and mostly on budget brands such as Prestige. Plus if you don't clean the coils on chillers yearly they start using more and more electricity as they run higher head pressures and tend to require acid washing annually because they're located much closer to the a/c pump strainer IMO.

Yes, a split system has 4 braised connections, 2 at the compressor and 2 at the air handler, both are usually easily accessible and can usually feel oil on them if you've got a freon leak.

They all have their place, but the package units while not lasting as long as a split system are easy. They almost NEVER need recharging as you don't have to break open the factory seal on the charging ports when installing them. Easy to change. Noisier than both split and chillers but not too bad usually. I installed a Marine Air 16k btu 410F unit 2 years ago and the a/c out of the vent measures 34F and with the turbo blower it moves a lot of air. The temp out of the 2 2007 R 22 units in the same salon area only pump out 44F and 46F out of the vents. When they had R417 in them, they really sucked and the temps out of the vents were 54F and 56F until I had them converted to R22, which is what they were initially designed for anyways.

A 16k btu chilled water fan coil puts out 16k btu's of cooling capacity IF you have 46-48F degree chilled water AT the unit (that particular air handler), which is almost never the case. If the chilled water happens to be 65F at that unit, you're probably getting 12k btu's of cooling capacity out of a 16k btu fan coil (guessing). The further each fan coil is from the chiller, the less efficient it is at cooling. The heat from exchanging the cooling of the chilled water to cooling the air, adds load to the chilled water loop, each subsequent unit down the line is getting water that is less cold from both the units that are on before it, and cooling loss simply from being pumped from so far from the chiller (lines losing a little to the ambient air through the insulation).

Directly from Dometics website:
Chilled Water Air Conditioning
Ideal for vessels 70 ft. (21 m) and over, chillers installed in the engine room circulate fresh water to air handlers installed in living and working areas.

http://www.dometic.com/USA/MS-11346...oning/PG-12465-Chilled-Water-Air-Conditioning

Hey Rover, firstly if you do have a refrigerant leak as it seems from what you've listed above you should concentrate on sorting that out first. You've indicated you have a split system so there are several places to check. Most commonly found leak points on those systems are the flare nut fittings and 3-way isolation valve stems at the condensing unit. I wouldn't want to replace a condensing unit only to find out a month later that there is a leak at the evaporator or some other part of the refrigerant circuit. This is why it is crucial to pump the system up with nitrogen prior to pulling a vacuum and re-charging. You want to ensure a leak free refrigerant circuit. These are all basic things a reputable outfit will do.

Most times when people replace the condensing unit they will also replace the evaporator,blower, and control circuitry at the same time. IF you do not wish do replace the evaporator assembly and control circuitry that is fine, several manufacturers make retrofit kits that allow you to use your original 3 knob controls with the newly installed equipment.

In my experience working for Dometic years ago there are not brazed fittings on the condensing unit nor evaporator from the factory but rather flare nut fittings. You can certainly have all of the refrigerant fittings brazed as it is a much more reliable connection in my opinion. However just know it is more labor intensive installing and removing when the time comes.

Pascal--I'm considering a chilled water system for my boat as well. AC units are 16 years old and showing their age, both in terms of not cooling well enough, and in terms of noise. Plus the boat has SIX self-contained units (4 in the salon and staterooms, and 2 for the bridge/aft deck). Total BTU's I think is around 105,000. I'm assuming that a chilled water system that large wouldn't be much more of an investment than replacing all 6 of these units over the next few years. Any thoughts/advice?

Call DS Marine in Brick. They are very good, maybe they can find the leak and save you a few bucks until you are ready to replace when you are sweating bullets.....

A lot more expensive to go chilled water. Routing all the chilled water lines and insulating them would be A LOT of labor in your boat. Plus I would NEVER go with 1 chiller for an entire boat. Always 2 chillers (or more). The self contained units are a very easy swap to a new one if there is access..... A handful of wires and 2 water lines, a duct hose and a couple of mounting bolts that's it. Generally it's $3200-3500 a unit to replace including installation.

The 92' Viking has 2 6 ton chillers for a total of 12 tons of air conditioning. See page 20, the first line under MECHANICAL.

"

Air conditioning - chilled water, 12
tons (two 6 ton units), zoned with
reverse cycle heat for complete
climate control throughout the
interior and with individual
temperature controls for staterooms
and salon
•"

https://www.dropbox.com/sh/3s2h4j8a...PMvoa/92EB_Brochure_12-2015-RM_Final.pdf?dl=0

Most 60 meter yachts have 3 chillers and generally have 2 in use in tropical climates and the 3rd is a spare. Perhaps that's what you're mis-understanding about "2 stage and 3 stage chillers" which is terminology I have never even heard before when talking about marine chillers. They are totally seperate chiller units and the 2nd stage and 3rd stage are 2 different chillers and set to come on 1-2F higher than the 1st chiller.....so if the 1st cannot keep up, then the 2nd chiller comes on.

If you lose the one chiller, and only have 1 chiller, you have NO a/c for the entire boat. Try telling that to the owners when you're sitting in Staniel Cay in the middle of nowhere with no support at the start of their 10 day trip. Most new yachts have no opening portholes and no opening windows and very few deck hatches, so the yacht is pretty much unlivable with no a/c.

Every chiller boat I've ever managed and run has had at least 2 chillers, some of the larger yachts even had 3. Neptunus puts 2 on all of their boats from 55' and up, the Hampton I manage has 2 as well. I think the only yacht I've run that had only one was a 50' Prestige. On all of these boats, 1 chiller would pretty much keep the whole boat comfortable with the exception of middle of summer and then the second one helps quite a bit. Redundancy is key.

Quite honestly, all you seem to want to do is refute everything I post. You're in over your head when it comes to completely understanding a yacht chilled water system. You argued with my post on how to take care of Awlcraft 2000 and Alexseal topcoats, when what I posted was DIRECTLY from the paint manufacturers "care and maintenance" section on their website. If you're just a googan, don't post on things you're not knowledgable about trying to act like you do.

To add to this. There is no such thing as a 2 stage chiller and 3 stage chiller. They are totally seperate chillers that the water loop goes through. Each chiller has a slightly different temperature set point so they don't both cycle on and off at the same time and pop shorepower breakers. You may have chiller #1 set to keep the loop at 46F and to come on at 48F, and chiller #2 set to keep the loop at 48F and to kick on at 50 F. Now at night and times of low demand chiller #1 will be able to maintain it's loop temperature of 46F by itself...... but when the sun is blazing and it's really hot out and all or most air handlers are calling for cooling at the same time, chiller #1 won't have enough cooling capacity to keep the loop temp between 46-48F, so the chilled water reaches 50F, chiller #1 is already running, chiller #2 comes on and brings the loop temp down to 48F (or wherever you have it set at) and then cycles off. But these are seperate units, you could turn the breaker completely off for chiller #2 and chiller #1 will operate as normal. If #1 goes down, you can run chiller #2, even adjust the temperature set points, and it will usually cool the entire boat pretty decently if not completely depending on how it's sized. But they are totally SEPERATE chillers. Problem is whatever chiller you have set as slave (higher set points) is usually always short cycling. So I swap them back and forth from slave and master every so often.

The 63' I am managing now has 2 seperate 4 ton chillers, it has 2 sea water pumps (only uses/needs 1 running) that I can valve and switch power to whichever one I want, and it has 2 seperate chiller loop pumps that only needs 1 to operate and can valve and switch power to the one I want. So the only time there would ever be a lack of air conditioning, is a leaking chilled water loop connection, or a plastic bag in the sea water intake. At the dock I leave 1 chiller on and the other one off, and it does fine without the 3 flybridge units running.

Problem with the entire setup is, if you only have 2 units running in the boat, when one calls for cooling you have 2 oberdorfer pumps come on (sea water, and circulation pump) and then also a 4 ton chiller compressor.....it's a lot of amperage to cool just the salon and pilothouse or say 2 staterooms.......and chiller cycling on and off and on and off very often......Chiller yachts (say under 80') use a ton of electricity just sitting at the dock and only a few units on to keep electricity down. The 55' Neptunus express with 3 small staterooms used to chew through $250-300 per month in electricity with only 1 of the 3 ton chillers on and only a refrigerator/freezer and battery charger . Other issue is they don't automatically change over to heat, you have to manually switch them over by hitting a toggle switch wired to the chiller (should shut the chillers down for a few minutes before hitting the switch for the reversing valve/heat). Entire boat either has a/c or heat, but not both, some have auxillary heat now but that's a pretty uncommon thing.

Here's an explanation of how they work and "staged" which most people never use the word staged, You'll just say yeah that yacht has 3 chillers and we have an issue with chiller #1, but each stage is a completely seperate chiller unit in entirety(condensing unit). Nobody in the general yachting word uses the word staged for them.
http://www.beardmarine.com/?q=air-conditioning/32/staged-chiller-water-scg

That's a pretty innacurate statement to make in my opinion, though that may not mean much here since I don't post often. Seems as though you only deal with Cruisair or Marine Air style rotary or scroll compressors in small vessel installations.

For instance several 50M+ yachts i've served on utilized the Copeland 06E compressor, this is a 6 piston compressor of which can be set up in several different fashions depending on the demand of the systems and installation restrictions. The 06E can be set up to have an unloader valve(s) for one or two sets of it's six pistons. The unloader valve acts as a bypass valve for banks of 2 pistons in the compressor, when it is open the refrigerant is not being compressed but rather re circulated in the cylinder head, thus the compressor is not running at full capacity. What the unloader valve does can be based on the chilled water loop temperature or the head pressure. Meaning you can have two types of unloaders electric or mechanical. Normal setups ups like this the 6 piston compressor starts with just 2 pistons actually compressing refrigerant, the other four are operating in a bypass mode via the unloader valve. If the the loop temperature increases or maintains constant with just two pistons of one compressor operating for a pre determined time the unloader valve closes which in turn now brings in two more of the 6 pitstons available in the compressor, this obviously increases the capacity of the compressor and the amperage also increases. If the loop temperature does not drop for a certain period of time(which can be pre set to the end users preference) the second unloader valve closes bringing on final two pistons, now with two unloader valves closed all six pistons are pumping refrigerant through the evaporator cooling tower and the Copeland 06E is operating a full capacity. That is one compressor mind you, most boats over 50M in my experience have a minimum of two more often then not a total of three or four. This process is running ONE compressor in different capacity STAGES based on what the loop temperature demand is.

Copeland o6E's have been around for a long time, and the unloader valve setup is seemingly how some compressor staging was accomplished prior to the advent of frequency drives. End of story is you can have one 06E operate through one or two capacity stages prior to the next compressor coming in and so forth. Maybe I didn't explain it best and someone else with experience on this equipment could chime in, but that's how I see it.

The thread is talking about yachts and so was the op in it. He had a 46 FOOT Post remember, and Pascal a 53 FOOT Hatteras MY. Not some 100 meter mega yacht, nor a cruise ship, nor a freighter, or even over 50 meter. 85% of the people posting technical questions have yachts under 100' on here. You can't come on here and give them advice of what a cruise ship does or megayacht as the systems and application are totally different.

If you look at the breaker panel or control panel for any chiller on the yacht, they're labeled Chiller #1, Chiller #2, etc. etc. Usually 150' and under they're designed to work together and installed by the builder and not even next to each other in a row, I've seen them one on top of the other, one over here, one 4 feet away......etc. etc. They are not on a single platform.

Take the 92' Viking SF you referenced. Viking calls them "2 6 ton units". It has 2 completely seperate dometic chiller units, that operate totally independant of the other one. The only thing they share is the chilled water loop that runs through the entire boat and sea water pump/line that cools them off. If you look on any of the breaker panels on these yachts, they will be labeled chiller #1, Chiller #2, Chiller #3. They are sold independently, in fact dometic calls them chiller modules. If one compressor unit/chiller goes out you don't replace all of them, you just buy one chiller mount it on the rack next to the functioning one and connect everything. The ONLY thing that "stages" them is you go into the control unit of each chiller and stagger the set points (temps) for start up and shut down points so they come on one after the other and not all at the same time.

For all intensive purposes and what we're talking about, Dometic is the largest seller of marine chiller units in the 50m< size worldwide by a long shot.

A single dometic chiller on Dometics website is called a "Dometic chiller module" which means it's a complete individual functioning unit that can be combined with other ones. And their custom "multi stage chiller modules" here is the description:

"Custom multi-stage chillers combine two to six chiller modules on a single platform. These systems address the BTU requirements of larger vessels that a single chiller unit cannot achieve. Multi-stage chillers have built-in redundancy, ensuring the system will function even if one of the circuits malfunctions."

http://www.dometic.com/USA/MS-11346...oning/PG-12465-Chilled-Water-Air-Conditioning

You're splitting hairs and inaccurate. The 2 stage chiller on the Viking you refer to IS NOT ONE CHILLER. It is two seperately functioning chiller modules so you have redundancy and can run 1 of the chiller modules totally independant of the other one. Or just run 1 of them to cool the boat when there is reduced demand. Each stage or module is a seperate chiller unit.

It's like a 39' Seavee center console with 3 outboards. They all work together to propel the boat, they all may share the same fuel tank and steering, but just because they are all connected together with a steering tie bar, they are still seperate outboards and still 3 outboards. If you blow a powerhead on one engine, the other 2 still function independantly of the blown motor and the other 2 will still propel the boat albeit at a reduced speed capacity.