Best way to Winterize marine Air conditioners

The marina guys here all all about efficiency & have a contraption that is like a suction cup and a hand pump.
After the boat is blocked.
They put the A/C raw water pump suction hose into a bucket of anti freeze, duct tape over the discharge ports on the outside of the hull, put the suction cup over one hole at a time and draw the antifreeze through the system at one hull through hull at a time. Un-taping the hole in use of course and re taping each hole as they go.

I never really scrutinized the contraption up close though as I never needed it.

In theory it could be a 1 man job if the bucket were big enough.

It is possible that their contraption is home made.

I'm reasonably sure. Our systems are self-contained Dometic Turbo reverse cycle units, gives AC and/or heat depending on system and thermostat setting, each has its own has onboard blower.

I've assumed OP's systems are all self-contained units, too, partly since they're about as common as dirt.

-Chris

Mapism. Most cooling units in the USA on boats of the size we have been discussing are self-contained reverse/cycle units which only require an open salt water circuit to operate. You may be familiar with different units.

The stand alone units generally used here can have their own salt water pump for circulation of salt water or can use one pump for multiple units. The OP apparently has 5 reverse cycle units serviced by one pump. The units are probably spread around the boat (salon, bedrooms, bridge,etc). For instance my units are located in the front berth, the master berth and beneath the salon. Each is suitably ducted to at least 2 locations per unit to distribute the cold/heated air generated at the unit. The discharge line will probably not have interior shut offs at the thru hull because they are probably 6 - 12" above the waterline.

Why don't you ask the yard to do it this year. Watch how they do it, then you're all set for the future years? Cracked hardware is not cheap.

Dunno if called "air handlers" or not, but there's a built in 6-speed blower on each unit pushing hot/cold air through all the ducting.

Our set-up is one unit in the saloon for saloon (lots of windows)and one unit under the master berth for master and guest stateroom, head, and galley.

In another post you asked about noise; yes, we can hear the compressors when they kick on. Not particularly overbearing. The Turbo units can have an optional sound shield installed, and I may look in to that sometime... But it happens our Turbos are very new to us, only installed this season, and they're quieter than the previous Marine Airrrr Vector Compact units.

-Chris

I think it doesn't matter which AC unit you turn on... I think any of the 5 will cause the pump to come on, and then the pump will be servicing all routes at the same time. You can test to confirm that...

-Chris

It's really quite easy, any AC unit will get the water pump running. Just need a bucket and for your boat maybe two or three gallons of antifreeze and it will come out all AC thru-hulls. I have two 16000 BTU compressors only in the engine room double stacked to which one has one big air handler on it and the other unit has three air handler on it. No water goes to the air handlers. Only to the compressor loop around the compressor and back out to cool things down. Or make heat in reverse cycle. Our units are not self contained.

You probably have five AC units in your engine room stacked and side by side to which your one water pump feeds all five. Not sure why you have so many discharge thru-hulls. I would think it's just one big one. But you said it's not. I guess you have a thru-hull for each compressor.. Anyway you have a big AC pump moving a lot of water, it takes a lot of water pressure to feed five units with one pump. Hence it take a lot of antifreeze pressure to feed five units....

Yep. The top diagram illustrates our system well, aside from actual placement and discharge routing. OP's Carver setup is likely similar, although with 5x compressors instead of 2x.

Normal ops, raw water enters pump and then routes to all compressors and then overboard. Winterizing, antifreeze goes to pump and then routes to all compressors and then overboard. In ours, any one compressor will activate the pump, and fluid routes to/thru all compressors, then overboard. Likely the same in OP's Carver.

-Chris

Yep, same in my 2009 Californian. One pump, sea water in. Activated by any unit. All units get sea water and discharge. I have Four compressors.

I don't love the noise as mapism correctly pointed out.

I won't condsider retrofitting to the Chiller system unless more than one of the four compressors dies.

Other than noise and space usage, what are the advantages of one chiller for all air handlers over all separate compressors?

I have a carver 396 with 3 ac units (reverse cycle). We struggled to find a good way to winterize ac units also. Just some background on this unit. We have a single water pump that supplies sea water to a water manifold that in turn ,sends water to all 3 units at the same time. So when trying to winterize these units using the pump to push antifreeze thru the lines. The antifreeze or any liquid would follow the path of least resistance. So it would winterize the shortest water line run very well ,but would not make it to the others. So the first year we had it ,we disconnected each line and pushed antifreeze thru them 1 at a time with a small pump. Year 2,I put 3 shut off valves at the water manifold. Now we use the ac water pump and just open 1 valve at a time to flush with antifreeze.