I leave the valves closed and add antifreeze down the drains as well as into the black tank.
Joe, Joyce , 4 Kids and 3 Dogs.
2004 V-10 Excursion with Hellwig sway bar, Roadmaster Active Suspension, Bilstein shocks and steering stabilizer, Super Duty Tow Mirrors,
3.73 Gears, Reese dual cam, Prodigy brake controller.
2010 Jayco Jay Flight G-2 32 BHDS