YOU CAN WINTERIZE THE A/C ONE OF TWO WAYS. REMOVE THE DISCHARGE HOSE THAT LEAVES THE BOAT FROM THE LARGE BALL VALVE, FLUSH BACKWARDS WITH WATER TO REMOVE ANY DIRT OR SILT, AND PUMP ANTI-FREEZE IN EITHER FORWARDS OR BACKWARDS WITHOUT USING YOUR PUMP. YOPU WOULD NEED A SMALL BILGE PUMP IN A BUCKET OF ANTI-FREEZE.
YOU WOULD NOT BELIEVE THE AMOUNT OF DIRT THAT WILL COME OUT OF YOUR CONDENSER BY BACK FLUSHING IT.