“I spent the afternoon with my neighbor who has great experience and understanding of winterizing. We removed the hose before it goes into the A/C cooling pump under the steps and ran pink RV anti freeze (AF) into it and then started the system and waited until the AF was shooting out of the discharge on port overboard flow. Need to wet vac out strainer and open A/C valve to seawater once out of the water. Also ran freshwater tank dry from washdown silcock and filled with 5 gal of AF and ran sink and shower lines until AF came out and sent most of discharge into the head and drains. Pumped out holding tank and then ran AF from head into holding tank. Still need to open up ball valves in aft compartment and for head to let seawater drain and then run AF through drains and seawater pump. I think that I should also remove the feeder pipe from the front of the head and suck up AF to run thru the pump and into the bowl instead of just running it thru the bowl and out the discharge line(s). Not sure what “”Y”” valve does for head – would guess that one position goes directly overboard and the other goes to the holding tank. I can flush with valve in either position, just to be safe.
As you recommended, blowing out the lines is fine, once they are filled and purged with AF. I know that you are in FL and may have a lot of experience with winterizing but I wanted to share with you what we did and have you think about where we might be missing something. “