Hayward GLC-2P-A Solar Pool Heating Control System with 3-Way Valve, Actuator and 2 PC Sensors Solar pool heating control system comes with 2 by 2-1/2-inch 3-way valve, actuator and 2 PC sensors Automatically maximizes solar heat collection by actuating a 24V valve when there is solar heat available Includes LED indicators that shows status of system operations This system provides recirculation freeze protection and installer-programmable features for any-system adaptability Quick, accurate, easy-to-set desired temperature controls