Winterizing A/C System

I'm not an expert on much, but I'm especially uneducated about marine a/c systems. My boat has two aquaair units. Both sit in the engine room. There is a water pump that feeds both units. I know to winterize it, I run antifreeze through the hose to the pump until the outlet water is red.

I like to use the boat year round, so my question is really about potentially not winterizing the units. Under the flybridge station, there is a chiller (I think that's what it's called). My dumb question is whether or not there is water running through the coils of that chiller. If so, I would need to winterize the system. If not, and the water only runs through the units in the engine room, I could not winterize the system since the bilge heaters would keep them from freezing. I'm in the South, so we only get a few weeks of very cold weather.

Does that make sense? Reverse air heat worked fine on my last boat, but this setup is a bit different. Thanks for any input.

I can only guess what the so called chiller might be. But first let me describe the two types of installed marine air conditioning systems:


Self Contained/Combined- In these systems, the compressor, the condenser (where Freon goes through the inside pipe and sea water goes through the outside), the fan and the evaporator coil where Freon boils off to absorb heat are all in one package. These are similar to a house window unit.

Split Systems- In these systems there is a separate compressor and condenser unit packaged together and sea water goes through the coil on these just like the self contained systems. But the Freon is transferred in tubing to remote air handler or evaporator units. In most cases there are two or more air handlers for each compressor unit. These are similar to a home central air system.

Given that you have two packages in the engine room, my guess is that you have two split systems and 2-4 air handlers throughout the boat and maybe one at the flybridge..

So what the heck is at your flybridge helm? All I can think of is a remote air handler to provide cooling at the helm, although it might be a self contained unit. A self contained unit would be unusual because of the head required to pump the sea water up there.

Look at the "chiller" and see if there is rubber hose which supplies water. If there is it will be connected to the condenser with hose clamps. Freon tubing does not use hose clamps ;-). I seriously doubt you will see that. If no rubber hose then no sea water to worry about winterizing.

My guess is that your A/C system will be fine without winterizing if you keep the bilge and locker that has any self contained unit in it above freezing.

And FWIW it takes me about three minutes to winterize my self contained A/C system and a half gallon of antifreeze. Yours is bigger with at least two condensers it seems, so maybe it will take a gallon.

David

Thanks for your response, David. I did a little more research and I think you are right that they are air handlers. There are three air outlets in the boat: one each in the forward and aft staterooms (handled by one control) and one in the salon. The salon air handler is the one that is under the flybridge fiberglass and it blows directly down into the salon.

I was pretty sure that water didn't go to those units, but the one in the forward cabin sounds like it has water running through it when it's on. The sound is not constant, but a steady beat. It has an attached fan, so maybe its the bearing in the fan, but it doesn't sound like it. That is what really had me questioning where the water was going.

I'm with you on how simple it is to winterize, but I'd rather not use space heaters all the time. I'll probably break down and winterize it, but I wanted to better understand my options.

Also if you are in saltwater I'd prefer to flush out with non toxic antifreeze, less corrosive then salt water and freeze protection.

No saltwater here. Nothing but clean, fresh Mississippi River water.

Freon as it evaporates can sound a bit like water flowing.


David

clynn...

Here is a link to the Installation Operation Maint Guide for the split systems.

It does have a winterizing section and deals with both the raw water loop as well as the chilled water loop. There is a need to wintereize both but it states the antifreeze can be left in the chilled loop under normal operating conditions.

I'm not familiar with these as mine are self contained... however, if I understand how they work correctly the ER unit is the chiller unit uses raw water and contains the compressor & condenser.
The air handling units are separate and the cooling / heating is provided by a recirculated "chilled" fresh water loop. This also needs to be winterized w/ AF.
This is similar to an industrial / commercial heat / AC system that uses a heated / chilled water loop to multiple zones / air handlers.

The info states that the recirc loop should include fresh water make up source (from boat FW system?) I'm thinking that you MAY be able to add AF to the recirc loop, close the make-up and run the as long as the raw water loop including inlet & outlet AND any make up for the recirc loop are in heated space. (you may need to check / top-off the recirc loop periodically?

I'd suggest you confirm that this is really what your set up looks like and maybe talk to the mfg tech help line to confirm ability to run the system w/ AF in the recirc loop as long as chillers are in heated space.