My winterization plan is to drain the lines at the low point and leave the low point drain valve open for a few ice making cycles. The ice maker should vent and gravity drain through the system. But since I can't be sure I'm planning on then draining the HW tank, bypassing the HW tank, and then blow out the lines with air pressure (regulated to 40 PSI) through each faucet. Once I have free flowing air I close the faucet valves and pressurize the water lines with air until the ice maker stops producing ice. My assumption would be that the line is now blowing air when the ice maker is calling for water. Then close the ice maker line's valve before putting any antifreeze into the lines. With my old RV I blew the lines clear after putting in AF so less of the bitter liquid is stored in the lines through the winter. It makes flushing them faster in the spring. The blown out AF is then used in the drains and toilet.
To de-winterize I'll flush the lines with water until clear before opening the ice maker valve then run a few batches of ice through to be sure residual AF isn't in the ice.
Best I can come up for now with unless someone has another idea.
