The COMMBOX-600 is a “Plug and Play” controlled power distribution panel for frost protection, ice and snow melting projects. When receiving a signal from the sensor(s)m the contactors are activated, energizing your heating system. DIP switch settings determine how the zones activate. When programming your system, make sure DIP switch 1 is in the ON position. The program manual can be navigated by using the SELECT (+) to move forward or SELECT (-) to go back through settings.