Using home air conditioning units on a boat?

[skipmac]

Relative upgrading his Viking 56 sport fisherman. Latest project is the air conditioning system.

The boat came with five units. I believe that's five separate compressors with associated evaporators/blowers. He thinks the units are 7-8 years old and just spent a good bit on maintenance.

He's thinking about upgrading due to the age and hours on the units and is considering using home units, what he calls a split system. That I believe means a separate compressor/condenser with evaporators/blowers in the different cabins. The reasons, cost and simplicity by eliminating all the raw water pumps, heat exchangers, etc.

The compressor would be air cooled home unit installed in the engine room with a pair of Mann 1550 HP diesels. That doesn't sound like a good idea to me. Certainly in that heated environment the air cooling would be very inefficient and also lead to a shorter life for the compressor as it would run very hot. Also the smallest unit he could get would be rated for a house at least double the volume of the boat so it would be running much under capacity which I think is not recommended.

So can any HVAC experts confirm my opinion that this would be a bad idea and why? On top of any other comments I could make I have to think that if it was practical why isn't everyone doing it.

[Coolerking]

What year is the Viking?
Where is it located?
Do the units he has now work?
I have worked on too many to count.
It's a bad idea because it won't fit.
The engine space is already legendarily tight.
Seawater condensers are tiny compared to the air cooled condenser you would need.
Not to mention the fact that the engine blowers would need to be much larger than stock and they would be running 100% of the time.

Fix the Cruisair units with SMX 2 controls.

[skipmac]

I think the boat is a 2008. Been in the engine room and it didn't look that tight to me but then I'm more used to 30-50 sailboats and compared to them his engine room is huge.

Boat is currently in MA. Florida for the winter.

I think two of the units are not currently working but not sure of the details. I know he's having error codes (HP I think but will ask) that seem to relate to the water cooling but he had the system flushed which helped but didn't solve the problem totally.

He's a builder and has installed a bunch of units in the homes he builds and seems to think one will fit. I have to say I'm skeptical having looked at plenty of home ac units and they don't look like they would fit to me.

[Coolerking]

First make sure each unit starts the pump on its own via the pump relay box, do them one at a time.
Change out the hoses, make sure the condensers get flushed, do them one at a time.
Make sure the manifolds are completely clean.

If you haven't serviced the seawater pump, and its a bronze head, (In which case it's either a Scott or a Price or an Oberdorfer) then buy a seal and impeller kit for it.
This is actually the most common thing I deal with...worn out/non op pumps, hoses, strainers.
Keep in mind that units that are tied to seawater manifolds can be starved for water due to obstructions and a eroded pump impeller and pump head.

[Lepke]

Home units are not made with marine environments in mind. The metals corrode, internal wiring connections, contacts may give you trouble.

I use chilled water. A unit in the ER is cooled by sea water, chilled coolant is plumbed thruout the boat to forced air units, one or two in each cabin. In the winter the same units supply heat with hot water thru the same plumbing.

[Coolerking]

Originally Posted by Lepke

Home units are not made with marine environments in mind. The metals corrode, internal wiring connections, contacts may give you trouble.

I use chilled water. A unit in the ER is cooled by sea water, chilled coolant is plumbed thruout the boat to forced air units, one or two in each cabin. In the winter the same units supply heat with hot water thru the same plumbing.

The amount of labor involved and the end result of trying to put a Tempered water loop in an already built Viking sport fisher would break most humans backs, wallets, and hearts.

[Sailmonkey]

I do boat air conditioners, 2008 isn’t that old, the problems are all solvable.

Putting an air cooled mini split into the engine room is such a bad idea on so many different fronts.

1. It’s not designed for the ambient temps of an engine room

2. The evaporators/condensers are not designed for installation into a structure that moves

3. It’ll just look like a cheapskate owned a Viking sport fish.

4. Knock $10k-12k per unit off of the selling price of the boat when it’s sold. Someone else will want to remove these things and put proper marine split gas units back in.

[Chotu]

I’m all for it but why on Earth would you install these compressors in an engine room?

All other issues can be overcome, but the condenser unit must go outdoors.

[Coolerking]

Originally Posted by Chotu

I’m all for it but why on Earth would you install these compressors in an engine room?

All other issues can be overcome, but the condenser unit must go outdoors.

Actually, they cannot be overcome, the evaporator are not designed for something that moves, the condensate will be a big problem, the coils are not designed for the marine environment, the linesets are not designed for the marine environment,
Not to mention that they have to mount on a wall.

The answer is no.

[skipmac]

Thanks all. Excellent details for talking SiL out of this plan.

[Chotu]

Originally Posted by Coolerking

Actually, they cannot be overcome, the evaporator are not designed for something that moves, the condensate will be a big problem, the coils are not designed for the marine environment, the linesets are not designed for the marine environment,
Not to mention that they have to mount on a wall.

The answer is no.

Says the guy who makes a living installing “marine” cooling systems.

The answer is yes. Thousands of people use residential air conditioning units on boats without incident. They are far more reliable (no circulation pump, zincs or through hull to deal with) and they can be replaced easily and cheaply if needed years down the line.

I’ve seen several boats with working mini split systems and have even seen them in RVs. A far more punishing environment than a boat. They slam around in ways boats will never see traveling.

The big drawback is having to mount the evaporator on a bulkhead. That’s what kept me from using a mini split in my boat. I have to maintain 360 degree visibility.

They do, however, make a drop ceiling evaporator for mini splits but it would reduce headroom terribly in most boats.

[Stewie12]

Most house AĆs these days are Invertors.

[GoneDiving]

Originally Posted by Chotu

The answer is yes. Thousands of people use residential air conditioning units on boats without incident. They are far more reliable (no circulation pump, zincs or through hull to deal with) and they can be replaced easily and cheaply if needed years down the line..

Next you will be suggesting that domestic fridges and exterior paints will be able to be used on board. Heresy. ��

I come from a technical diving background where everything is labelled "Life Preserving" and comes with a 4 fold price tag and one supplier in town. As a newbie, I'm seeing a lot of similarities to boating. Sorry to sidetrack the thread: Rant off

To the OP, I'd agree that an engine room would have to be the worst place to fit the evaporator. Here they go outside where ever convenient and away from direct spray

Cheers.

[CaptDHill]

Shrimp boats and other workboats do often use air cooled condensers. However, the condensers are located on an upper deck or somewhere in the open air. An air cooler condenser absolutely will not work if located in an engine room unless the condensing coils are about as large as the boat. Notice I said large as the boat; not large as the engine room. To the gentleman who said, “Yes it would work,” I disagree. I don’t know of any home units installed in an engine room functioning. It isn’t scientifically not possible with standard air cooled coils.
I also differ in the opinion that an RV environment is harder on a system than the marine environment. Not to be ugly here, but this individual has either never been to sea or has forgotten what the open ocean can do to a boat. What roads are those RVs traveling on that are more destructive than the ocean and its wind and waves? No offense, but I question that idea.
I forgot the size of the subject vessel, but a pair of chillers that take turns is most likely the answer.
I have never seen an outdoor condenser on a proper yacht. I have seen many though on workboats and junky home jobbers but always with the condenser located in the open air.

[Chotu]

Originally Posted by CaptDHill

Shrimp boats and other workboats do often use air cooled condensers. However, the condensers are located on an upper deck or somewhere in the open air. An air cooler condenser absolutely will not work if located in an engine room unless the condensing coils are about as large as the boat. Notice I said large as the boat; not large as the engine room. To the gentleman who said, “Yes it would work,” I disagree. I don’t know of any home units installed in an engine room functioning. It isn’t scientifically not possible with standard air cooled coils.
I also differ in the opinion that an RV environment is harder on a system than the marine environment. Not to be ugly here, but this individual has either never been to sea or has forgotten what the open ocean can do to a boat. What roads are those RVs traveling on that are more destructive than the ocean and its wind and waves? No offense, but I question that idea.
I forgot the size of the subject vessel, but a pair of chillers that take turns is most likely the answer.
I have never seen an outdoor condenser on a proper yacht. I have seen many though on workboats and junky home jobbers but always with the condenser located in the open air.

First, I don’t think any poster in this thread said installing the condenser in the engine room would work. Scroll back to take a look. It would never work. Has to be outside.

Onto RVs: The ocean provides a smooth bouncing and rolling environment. The roads slam things. Hard. I was speaking to the Thermoking who said the condensers couldn’t take the motion of a boat. They can. And easily do. They even take the much harder impacts of an RV.

Guess you probably don’t own an RV to think the smooth motion of sea is higher G forces than taking an RV cross country. Road bumps are way higher g forces. The boat has a larger amplitude motion, but the change in amplitude over time is small. The RVs are brutal on equipment, if used for traveling.