JADE W7220 Economizers are used with CO2 sensors and solid state C7400 Enthalpy Sensors or C7660 Dry Bulb Temperature Sensors. The unit proportions outdoor and return-air dampers for control of free cooling in commercial HVAC equipment. W7220 Economizer Module can be configured for 4 different economizer strategies: referential or differential dry bulb, referential or differential enthalpy. The W7220 Economizer Module can be used as a standalone economizer module wired directly to a commercial set back space thermostat and sensors to provide Outdoor Air dry-bulb economizer control. The W7220 Economizer Module can be connected to optional Sylk Bus sensors for single or differential enthalpy control. The W7220 Economizer Module provides power and communications on the Sylk Bus for the sensors. The W7220 Economizer Module automatically detects sensors by polling to determine which sensors are present. If a sensor loses communications after it has been detected, the W7220 Economizer indicates a device fail error on the display or through the AUX 1 OUT terminal programmed to SYS.