Carrier 48TC series, Service And Maintenance Instructions, Page: 56 / 112

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Fig. 75 — W7220 Economizer Module
The W7220 economizer module can be used as a stand-alone
economizer module wired directly to a commercial set-back space
thermostat and sensors to provide outside air dry-bulb economizer
control.
The W7220 economizer module can be connected to optional
sensors for single or differential enthalpy control. The W7220
economizer module provides power and communications 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
controller indicates a device fail error on its LCD.
SYSTEM COMPONENTS
The EconoMi$er X system includes an economizer module, 20k
mixed air sensor, damper actuator, and either a 20k outdoor air
temperature sensor or S-Bus enthalpy sensors.
Economizer Module
The module is the core of the EconoMi$er X system. The module
is mounted in the unit’s control box, and includes the user inter -
face for the system. The W7220 economizer module provides the
basic inputs and outputs to provide simple economizer control.
When used with the optional sensors, the economizer module pro -
vides more advanced economizer functionality.
S-Bus Enthalpy Control Sensors
The sensor is a combination temperature and humidity sensor
which is powered by and communicates on the S-Bus. Up to three
sensors may be configured with the W7220 economizer module.
CO
2
Sensor (optional)
The CO
2
sensor can be added for Demand Controlled Ventilation
(DCV).
SPECIFICATIONS
W7220 Economizer Module
The module is designed for use with 2 to 10 vdc or bus communi -
cating actuator. The module includes terminals for CO
2
sensor,
Mixed Air sensor, and an Outdoor Dry Bulb sensor. Enthalpy and
other options are available with bus sensors.
User Interface
Provides status for normal operation, setup parameters, checkout
tests, and alarm and error conditions with a 2-line 16 character
LCD display and four button keypad.
Electrical
• Rated Voltage — 20 to 30 vac RMS, 50/60 Hz
• Transformer — 100 va maximum system input
• Nominal Power Consumption (at 24 vac, 60 Hz) —
11.5 VA without sensors or actuators
• Relay Digital Output Rating at 30 vac (maximum power
from Class 2 input only) — 1.5A run:
3.5A inrush at 0.45PF (200,000 cycles) or
7.5A inrush at 0.45PF (100,000 cycles)
• External Sensors Power Output — 21 vdc ± 5% at 48mA
INPUTS
Sensors
NOTE: A Mixed Air (MA) analog sensor is required on all
W7220 units; either an Outdoor Air (OA) sensor for dry bulb
change over or an OA bus sensor for outdoor enthalpy change
over is required in addition to the MA sensor. An additional Re -
turn Air (RA) bus sensor can be added to the system for differen -
tial enthalpy or dry bulb changeover. For differential dry bulb
changeover, a 20k ohm sensor is required in the OA and a bus sen -
sor in the RA. DIP switch on RA bus sensor must be set in the RA
position.
Dry Bulb Temperature (optional) and Mixed Air (required),
20k NTC
2-wire (18 to 22 AWG);
Temperature range –40°F to 150°F (–40°C to 66°C)
Temperature accuracy: 0°F/+2°F
Temperature and Humidity, C7400S1000 (optional)
S-Bus; 2-wire (18 to 22 AWG)
Temperature: range –40°F to 150°F (–40°C to 65°C)
Temperature accuracy: 0°F/+2°F
Humidity: range 0 to 100% RH with 5% accuracy.
NOTE: Up to three (3) S-Bus sensors may be connected to 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 57 for wiring details).
24 vac power supply
20 to 30 vac 50/60Hz; 100 VA Class 2 transformer.
OUTPUTS
Actuator Signal
2 to 10 vdc; minimum actuator impedance is 2k ohm; bus two-
wire output for bus communicating actuators.
Exhaust fan, Y1, Y2 and AUX1 O
All Relay Outputs (at 30 vac):
Running: 1.5A maximum
Inrush: 7.5A maximum
ENVIRONMENTAL
Operating Temperature
–40°F to 150°F (–40°C to 65°C).
Exception of display operation down to –4°F (–20°C) with full
recovery at –4°F (–20°C) from exposure to –40°F (–40°C)
Storage Temperature
–40°F to 150°F (–40°C to 65°C)
Shipping Temperature
–40°F to 150°F (–40°C to 65°C)
Relative Humidity
5% to 95% RH non-condensing
ECONOMIZER MODULE WIRING DETAILS
Use Fig. 76 and Tables 22 and 23 to locate the wiring terminals for
the economizer module.
IMPORTANT: All inputs and outputs must be Class 2 wiring.