Abstract: A current relay is connected in series with the electrodes of an electrolytic generator and controls the operation of a time delay relay connected in series with the operating solenoid of a water inlet valve. The time delay relay delays the opening of the water inlet valve for a predetermined time after the electrodes are energized and the current supplied thereto is less than a predetermined value.

Abstract: A Teflon tube is loosely fitted into a guide passageway in a metallic heat transfer member. The tube has a water inlet at one end and an outlet at its other end. One end of the tube extends freely from an end of the passageway and the tube is movable both linearly and diametrically in the passageway so that the tube can expand both in length and cross sectional area independently of the heat transfer member. The tube has a coefficient of expansion greater than that of the heat transfer member whereby the expansion and contraction of the tube as its temperature fluctuates loosens deposited salt crystals from the surface of the tube for expulsion by the water passing therethrough. The heat transfer member may be either directly or indirectly electrically heated. The space between the tube and passageway wall may be filled with a heat conductive material which is liquid at the operating temperature of the heat transfer member.