Air replacement.

You have seen the light then? The system I am running needs more power than many boats can deliver from their main engines, it has 4 compressors, 4 condensers and 4 plate cooler type chillers but only two of those chill the water to serve the rest of the vessel, if you are so knowledgeable CaptJ please tell the YF readers what the other two do and how they achieve it.

Just started running an 84 Lazzara sky lounge. Boat has the exact set up J described with two independent chillers, sharing the water loop and the raw water system.they are staged so that the second chiller only comes on if needed. At night, one chiller (60k btu) is enough to keep the boat cold. During the day both are needed although running on one will make the boat confortable enough if needed.

I really wish some would keep their replies in the context of the original posts. As much as I find it interesting to hear about systems on bigger boats, the Ac setup on 50m or bigger boat is pretty much irrelevant here... Not the first one a thread drifts off topic for this reason

Viking themselves states two 6 ton chiller units, they are 2 totally seperate chillers that are plumbed with the same water line and sea water line. They work either independently of one another, meaning you could use only chiller #1 or chiller #2, or you could use them in tandem for a total of 12 tons of a/c, you could set #1 as slave and #2 as master, or #1 as master and #2 as slave by simply pushing a button to adjust the temperature cut in and cut out of each unit. but either way, if chiller #1's compressor blows up, chiller #2 will still provide 6 tons of a/c to the chilled water loop or vice versa. They each are their own complete system and have their own circuit boards, high pressure and low pressure safeties, chiller controls, and chilled water temperature sensor. Whether they are mounted right next to each other, on the same stand, or across the engine room from each other, they are their own complete chiller module and work on their own independant of each other. A single chiller is one compressor module, PERIOD.

What you're posting is irrelevant to the topic. Please name any normal motoryacht or sportfish 100' or less that would have an H &H chiller system with a compressor unit with multiple heads?

The system you are running and the boat you are on are not relevant to this thread. We are talking about yachts here, NOT a megayacht and NOT a cruise ship. This thread is about yachts under 50 meters and actually under 100'. Send me a picture and I'll tell you what they're running. Best educated guess without even seeing what you have, would be for refrigeration and send compressed freon or compressed propane if the runs are long, but could be super chilled coolant to plates in the refrigerators and freezers. None of this has to do with a chilled water air conditioning system on a yacht under 100'.

How they work, as the compressed propane goes into the plate, it expands inside the plate as it flows through, causing it to get very cold which transfers to the air in the refrigerator or freezer. A solenoid or valve opens to allow the propane to flow through the refrigerator or freezer plate when the thermostat calls for cooling and then it flows back to the compressor unit where it is compressed again. Heat is probably transfered out of the boat/gas/system with a water to gas heat exchanger, salt water running through one side before it gets back to the compressor or at the compressor, the gas through another just like any other marine a/c system.

The 63' Hampton I manage is the exact same way and I would be more than happy to take a picture when I get to the boat on Monday, it has two 4 ton chillers setup the same way. They are on 2 totally seperate stands mounted on the wall one above the other with about a 1' in between. Only thing connecting the two is the insulated shared chilled water line. Control units for each chiller are totally independant of one another and so is every other aspect of the system. They do use the same circulation pump, but either unit will trigger it to run. They both use the same raw water pump, but again either unit will trigger it to run.

3 chiller units on the same stand stacked one on top of the other. There are 2 sets of gate valves on the right side of each chiller to shut off what looks to be the sea water line from each unit and there are 2 sets of gate valves on the left side of each unit to also shut off what looks to be the chilled water cooling line on the left side of the unit. So you can run 2 units and completely alienate the one you're not using (or even just 1 unit) and shut off both sea water and coolant(chilled water). 2 seperate coolant circulation pumps on the left side 1 on the bottom shelf and the second on the middle shelf. I would have used ball valves instead of gate valves as they're durable in the long run and it would have been easier to open or close them without busting your fingers and knuckles since the gate valves are so close to the stand and you've got to turn them 3+ revolutions versus a 1/4 turn. Those are 3 seperate units with their own compressor unit, heat exchangers, triggers for the raw water pump and coolant circulation pump, cut in and cut out set point thermostats on the top left of the top stand, each unit has it's own temperature gauge and pressure gauge at the front bottom of each unit so if you're just running one and have the valves shut to the other 2, you still have gauges for the unit you're running, they're just mounted on the same stand......you can run only 1 and completely take 2 whole units and throw them in the ocean after you shut off all of the gate valves to the 2 units you're throwing in the ocean and it will provide whatever cooling capacity of the unit itself. Looks to be about 6 tons each unit of a/c for a total of 18 tons. It's a nice setup and each chiller module can be 100% alienated from the others with the gate valves. You may want to have the boys that built it coil the excess electric wires on either the top or bottom circulation pump so that they match each other, it would look more professional that way.

Then why did you post a picture of a 3 stage chiller. There are 3 compressor units. Personally I would've gone with the new Dometic units with their titanium heat exchangers and the ability to get parts and techs trained on them on a 100' yacht. It's a heck of a lot easier to open the dometic manual and order part # xxxx high pressure switch and have it overnighted from a dometic dealer than search for something else after you identify what something else is. A very good friend of mine owns a company and builds chiller units and puts them on yachts 100-200'+. Either way, it is not relevant to the boats posted in this particular thread.

I get what you do and get what your knowledge base is. But quite frankly it's very different than production yachts made out of fiberglass or cold molded that are 100' and under and what the origional posters in this thread

The titanium has NOTHING to do with growth, it will just make the unit (heat exchanger) last much longer every time you acid wash the sea water side annually since the titanium is stands up to acid much better than copper.

Just what exactly do you think you are doing with the bypass valving. When you shut the valves you are isolating the unit. You are shutting off both coolant flow to the unit and sea water. With all 4 valves shut you could take the entire compressor unit off and run the remaining 2 units and the system wouldn't even know it's missing besides the loss of cooling capacity. Plain and simple.

Gate valves always have a tendancy to leak at the stem when they get old, ball valves both withstand more pressure and rarely if ever leak from the stem.

Last I checked there wasn't a Grainger in the BVI's or Europe or South America.

Perhaps you should check YOUR a/c subcontractors company for more explanation on chiller systems. Scroll down to the very bottom and see the diagrahm labeled "TYPICAL SEAWATER PLUMBING INSTALLATION FOR DUAL 15 TON CHILLERS WITH ADDITIONAL STANDBY PUMP" Note how the chiller modules/units are labeled chiller #1 and chiller #2 in the diagrahm. Note how the 4th diagrahm above it, the diagrahm labeled "PIPING INSTALLATION FOR CHILLER SYSTEM" only shows one compressor unit or chiller module in the diagrahm.

http://www.oceanbreezeac.com/chiller.php?dF=82&dC=28&hmd=84&wc=113&ws=0&reload

Here you go

Two 60k btu chillers sharing the same loop but otherwise independent of each other capable of running together or separately.

Again, fairly typical of the boats this thread is about, 60/90' not 150' or more

It's not about whether I'm right or wrong. It's about the OP and Pascal getting the right information for their boats that they're looking for. The a/c company you use, who built the 3 stage chiller you posted the photo of, have diagrahms on their website with the exact same verbage and terminology that I have posted previously in this thread. The diagrahms are very good and show a chiller system quite well. A project manager hires the right people to do the job correctly and knows about most everything they're doing, but obviously you're not a EPA licensed a/c contractor who specializes in air conditioning day in and day out. Neither am I, but I have dealt with tons of chiller issues, changing systems around that weren't right from the builder, and so forth and so on, on these yachts. As for changing around engine beds and things like that, that's not my field of experience and I just hire the right people for that, yet won't comment on it.