If using the CCRP with microprocessor based ETS room heating system(s) and utilizing the automatic charge control option, an outdoor temperature sensor is required. This sensor attaches to the two "OS" positions of the terminal strip in the CCRP. The outdoor sensor sends outside temperature information to the CCRP and the power line carrier transmitter within sends this information to the heater(s), eliminating the need for direct wire connections between the heater(s) and the CCRP.
NOTE: If utilizing the automatic charge control option with fluid regulated ETS room heating systems (i.e., Steffes "S" series heaters and most European models), the CCRP must be special ordered from the factory in this configuration.
If NOT utilizing the automatic charge control feature of the CCRP, a 4300 ohm resistor must be placed between the two OS terminals to prevent the 2100, 3100, 4100, or 5100 Series heating system(s) from displaying Error 6 (Er 06).