25EconoMi$erR X (Factory--Installed Option)C14154Fig. 39 -- W7220 Economizer ModuleProduct Description —The EconoMi$er X system is an expandable economizercontrol system, which includes a W7220 economizermodule (controller) with an LCD and keypad. The W7220can be configured with optional sensors.The W7220 economizer module can be used as astand--alone economizer module wired directly to acommercial set--back space thermostat and sensors toprovide outside air dry--bulb economizer control.The W7220 economizer module can be connected tooptional sensors for single or differential enthalpy control.The W7220 economizer module provides power andcommunications for the sensors.The W7220 economizer module automatically detectssensors by polling to determine which sensors are present.If a sensor loses communications after it has beendetected, the W7220 economizer controller indicates adevice fail error on its LCD.System Components —The EconoMi$er X system includes an economizer module,20k mixed air sensor, damper actuator, and either a 20koutdoor air temperature sensor or S--Bus enthalpy sensors.Economizer Module: This is the core of the EconoMi$er Xsystem, is mounted in the unit’s control box, and includesthe user interface for the system. The W7220 economizermodule provides the basic inputs and outputs to providesimple economizer control. When used with the optionalsensors, the economizer module provides more advancedeconomizer functionality.S--Bus Enthalpy Control Sensors: The S--Bus enthalpycontrol sensor is a combination temperature and humiditysensor which is powered by and communicates on theS--Bus. Up to three sensors may be configured with theW7220 economizer module. See page 26 for details.CO 2 Sensor (optional): A CO2 sensor can be added forDemand Controlled Ventilation (DCV).SpecificationsW7220 Economizer Module —The module is designed for use with 2 to 10 Vdc or buscommunicating actuator. The module includes terminalsfor CO2 sensor, mixed air sensor, and an outdoor dry bulbsensor. Enthalpy and other options are available with bussensors.User Interface: Provides status for normal operation,setup parameters, checkout tests, and alarm and errorconditions with a 2--line 16 character LCD display andfour button keypad.Electrical —Rated Voltage: 20 to 30 Vac RMS, 50/60 HzTransformer: 100 va maximum system inputNominal Power Consumption (at 24 Vac, 60 Hz):11.5 VA without sensors or actuatorsRelay Digital Output Rating at 30 Vac (maximumpower from Class 2 input only): 1.5A run:3.5A inrush at 0.45PF (200,000 cycles) or7.5A inrush at 0.45PF (100,000 cycles)External Sensors Power Output: 21 Vdc 5% at 48mAIMPORTANT: All inputs and outputs must be Class 2wiring.Inputs —Sensors:NOTE: A mixed air (MA) analog sensor is required onall W7220 units; either an outdoor air (OA) sensor for drybulb change over or an OA bus sensor for outdoorenthalpy change over is required in addition to the MAsensor. An additional return air (RA) bus sensor can beadded to the system for differential enthalpy or dry bulbchangeover. For differential dry bulb changeover a 20kohm sensor is required in the OA and a bus sensor in theRA. DIP switch on RA bus sensor must be set in the RAposition.Dry Bulb Temperature (optional) and Mixed Air(required), 20k NTC:2--wire (18 to 22 AWG);Temperature range --40 to 150_F (--40 to 65_C).Temperature accuracy --0_F/+2_FTemperature and Humidity, C7400S1000 (optional):S--Bus; 2--wire (18 to 22 AWG)Temperature: range --40 to 150_F (--40 to 65_C)Temperature accuracy --0_F/+2_FHumidity: range 0 to 100% RH with 5% accuracy.NOTE: Up to three (3) S--Bus sensors may be connectedto the W7220 Economizer module. For outdoor air (OA),return air (RA) and discharge (supply) air (DA).4 Binary inputs:1--wire 24 Vac + common GND (see page 27 for wiringdetails). 24 Vac power supply: 20 to 30 Vac 50/60Hz;100 VA Class 2 transformer.