[SVAuspicious]

when winterizing the system i disconnect the inlet & outlet hoses. i put a screwdriver in the inlet to hold the check open till all the water drains out , then connect the two hoses with a copper pipe. i can then pump antifreeze through the system and not put any in the water heater. you don't use as much antifreeze & do not have to flush the water heater when you flush out the antifreeze in the spring

That's a good approach. Some people with hard to reach water heaters install bypass valves that are easier to manage than disconnecting and connecting hoses every year.