Best way to Winterize marine Air conditioners

Close seacock and clean sea strainer bowl/basket. Create a way to supply AF. Pull AF through using the installed AC water pump AND at the same time push AF through using a separate transfer pump. Ensure AF being pumped overboard becomes visible at all discharge outlets.

The "create a way" can vary. I installed Groco "Safety Seacock" (SSC) adapters, essentially a T fitting for flushing raw water systems. Then I built a "flush box" out of a Rubbermaid (or some such) storage container, easy to keep full of AF. Added a spigot to the box, and use hoses from box to the transfer pump to SSC. Transfer pump pushes, AC pump pulls, relatively easy.

Could probably inject through the top of the sea strainer, maybe slightly messier. I've read some have created a flush adapter by installing a fitting in the top of the strainer, and I think there are purpose-built things like that one the market.

Tried using just the transfer pump but one of our loops is short, the other much longer... so everything the transfer pump pushed dribbled out the short loop.

-Chris

If you have centifical pumps, no If this is all new to you, hire a mechanic and watch his process for winterizing your boat. Next year do it yourself.

Yes. I described that as "pull" in my earlier note.

I suspect it depends. Our transfer pump is relatively small, and when I tried to use only that to push AF through -- i.e., without also turning on the AC pump -- all the AF simply took the shortest route to discharge. That meant one line, very much longer than the other, wasn't getting AF through. Had to also turn on the AC pump to get all lines treated.

Might be our transfer pump wasn't even really necessary... might be that just using the AC pump would be sufficient.

-Chris

AC seacock closed.
Open up the top of the sea strainer.
Have some one turn one of the units to the run position to get the water pump going, simultaneously pour in the pink antifreeze so you don't loose pump suction , from a small bucket. Two to three gallons should be more than enough. You need to keep the strainer bowl filled in order to keep the pump from cavitating. If it does cavitate. Shut the pump off, fill the bowl and start up the pump again keeping it filled. Pouring from a gallon jug will not keep up with the pump and it will cavitate.
Not sure how many AC pumps you have, you have to do it at each pump.
No need to turn on every AC unit, as one pump usually handles multiple AC units.
Make sure you drain the seacock and /or remove the hose from the seacock to the strainer to remove sea water so it does not freeze.

OR, buy a few feet of hose, the same size going to the intake side of the AC pump. Remove the hose end from the seastrainer to the pump intake, install the new hose to the pump intake, fill the hose with pink antifreeze. Fill a bucket with two ,or so gallons, keeping the hose filled stick the end into the filled bucket and turn on the AC pump till it comes out the boat AC thru-hull .

That's an excellent process, but requires two people if your pumps are in the ER and main breakers are in your salon. And a lot of work, imo. First you have to set each thermostat to run the units when energized. The you have to throw the breakers, then you have to go to the racor, close the valve set up a delivery system for the pink stuff, then go up to the breaker panel and start that unit, being sure that enough anti freeze went thru . If you have four independent units, that's x4 process . Verses going to each racor , screwing on the hose cap made for the job, and with a low pressure pump just pumping fluid thru. You can do that with a pump head attached to a battery powered drill. If you use a 5 gallon pail or single gallon jugs you can do it right out of the container. Just saying....

Each boat is just a bit different. My seastrainers a PERKO. No threaded top. Just a flat top with a gasket and two bolts on the ends with wing nuts to secure it with. Can't screw in a hose cap. You have to pour it in. Or remove the hose and pump it through with a pump as you said . You can do the longer spare hose a bucket method by yourself.

I gather many installations aren't independent units; ours, for example, is two ACs serviced by a single pump.

And then whether or not a small transfer pump will work maybe also depends on the installation. In our case, for example, the transfer pump would push AF through the short line (approx 12' to discharge) easily... but wouldn't push AF through the much longer line (approx 40' to discharge) for the AC that's furthest from the installed AC pump. IOW, everything just dribbled out the shortest route. Using the installed AC pump too solved that.

Our sea strainers are Buck Algonquin; no threaded cap. Hence our eventual installation of the Groco SSC in that line, so we can screw a hose to that.

-Chris

Gotcha, I missed that in your thread.

How do you know the other 4 units got 'juiced'. Shouldn't you turn on all the units? If the boat is out of the water you can backfill thru the thru hulls with a pump

I am a bit puzzled by this debate, so I am wondering if there's anything I'm missing.
I mean, any AC equipment (small boats aside) has two water circuits:
One with sea water for cooling the AC units, with its own pump(s), and of course this has to be winterized.
But the second is just a closed loop where fresh water is circulated through the fancoils by dedicated pump(s).
For this one, why don't you just mix antifreeze to the fresh water upon initial commissioning, and then forget it?

My system has Freon? for the closed loop, and an open salt water for the chiller/heater side. So I'm only winterizing the open loop

This fellow has one sea pump for all four units so naturally without running all 4 units simultaneously or using some direct method for each of the circuits the pink antifreeze will tend to seek the shortest line and he can't be sure he has adequately winterized all 4 units. I suppose if you introduced valves on each of the lines so that you could close then down in sequence they could be independently filled. By contrast each of my 3 units has a dedicated salt water pump which are easily winterized thru each of the three grocos. Having centifical pumps, I merely have to pump the pink stuff thru without running each unit. That can be done in reverse thru the outboard discharges as well with the proper pump.

Other's on this forum must have this similar set up, I'd be interested in how they winterize their units.

Hang on a minute, that's actually a third circuit, which I didn't consider in my previous post.
The refrigerant gas (freon, 410, or whatever is used nowadays) is fully contained - pressurized - inside the chiller unit(s), and of course doesn't need to be winterized.
For cooling the air handlers inside the boat, all systems I've seen use fresh water (possibly mixed with AF, which was the sense of my previous suggestion), pushed around by circulation pump(s).
This is the circuit which I didn't understand, from the previous posts, if someone was suggesting to winterize.

Anyhow, back to winterization of the sea water circuit: no idea about the Carver 98 particularly, but properly built boats normally have valves on all hull outlets.
If so, AND if each chiller unit has its own outlet (which is not always true), isn't it sufficient to check which of the outlets is the first to spit the AF, close its valve, and move to the next?

I have two AC units with one pump...I always use my AC pump to pump the anti-freeze through. The AC pump has more strength than a drill or small pump in a bucket.
Your five AC units run off one pump, when you turn on one unit in the summer, water goes through all units and out no matter if you run one , two, or all five, the water pump runs feeding all units with water whether they are ''on'' or ''off''.
I don't think you have enough pressure from your bucket pump to push through all long hose line runs etc, so it went out the easiest route when all hoses were connected to the AC pump.
Next time I would run a hose from the AC pump intake side into a five gallon bucket of anti-freeze trun on any unit to get the AC pump running and pump it through with the stronger boats AC pump. Then it will go through all five units at once.

Our AC systems have only two circuits: refrigerant, and sea water.

-Chris

We've got it down to 2 people. Me at the transfer pump and my flushbox attached to the Groco flush valve, wifey at AC control (first) then outside to monitor thru-hulls.

In our system, it doesn't matter which AC unit control we use to start the system; starting either AC starts the pump, and the pump feeds both ACs and discharge lines... so she can start the saloon unit and go outside to look at the discharge flow for both units.

That said, we only have two ACs and one pump; not sure if 5 ACs on one pump would work the same way.

-Chris