The solenoids that you mention are energized with the system "A" pump switches in the off position. The solenoids are electrically operated. With prolonged operation of the pump switches in the OFF position, the solenoid runs the risk of permanently jamming shut (like a magnet). Our company even states a limited time for the pump switches to be placed off after which a log entry has to be made in PDR. When you go home at night, by placing the Battery switch to OFF the solenoids are NOT energized.