Thanks to everybody for your help, installed 3 bypass valves, 1 in the main tank and 2 at the water heater, sure made it easy to winterize, now a good flush of the water heater as that was Pace's way of putting bypass valve in that was no good. A good flush of all lines in the spring and should be good to go. The owner is happy but decided to leave antifreeze in the lines for the winter????