22
W7220 Economizer Module Wiring
Use Tables 12 and 13 to locate the wiring terminals for the
economizer module.
Time-out and Screen Saver
When no buttons have been pressed for 10 minutes, the
LCD displays a screen saver, which cycles through the Status
items. Each status item displays in turn and cycles to the next
item after 5 seconds.
START-UP AND OPERATION
Cooling, Unit with EconoMi$er
®
X
For Occupied mode operation of EconoMi$er X system,
there must be a 24-v signal at terminals R and OCC (provided
through PL6-3 from the unit’s IFC coil). Removing the signal
at OCC places the EconoMi$er X control in Unoccupied
mode. See Table 14 for Damper Position Control.
During Occupied mode operation, indoor fan operation
will be accompanied by economizer dampers moving to Min-
imum Position setpoint for ventilation. If indoor fan is off,
dampers will close. During Unoccupied mode operation,
dampers will remain closed unless a Cooling (by free cool-
ing) or DCV demand is received.
When free cooling using outside air is not available, the
unit cooling sequence will be controlled directly by the space
thermostat. Outside air damper position will be closed or
Minimum Position as determined by Occupancy mode and
fan signal.
When free cooling is available as determined by the appro-
priate changeover command (dry bulb, outdoor enthalpy, dif-
ferential dry bulb or differential enthalpy), a call for cooling
(Y1 closes at the thermostat) will cause the economizer con-
trol to modulate the dampers open and closed to maintain the
unit supply air temperature. Default mixed air temperature is
53°F, with a range of 38°F to 70°F. Compressor will not run.
Should 100% outside air not be capable of satisfying the
space temperature, space temperature will rise until Y2 is
closed. The economizer control will call for compressor oper-
ation. Dampers will modulate to maintain MAT at set point
concurrent with Compressor 1 operation. The “Low T Lock”
setting (default 32°F) will lock out compressor operation
when outside air temperature is below setpoint.
When space temperature demand is satisfied (thermostat
Y1 opens), the dampers will return to Minimum Damper po-
sition if indoor fan is running or fully closed if fan is off.
If accessory power exhaust is installed, the power exhaust
fan motors will be energized by the economizer control as the
dampers open above the EXH1 SET setpoint and will be de-
energized as the dampers close below the EXH1 SET set-
point. (For single speed unit.)
Damper movement from full closed to full open (or vice
versa) will take between 1
1
/
2
and 2
1
/
2
minutes.
Heating with EconoMi$er
®
X
During Occupied mode operation, indoor fan operation will
be accompanied by economizer dampers moving to Minimum
Position setpoint for ventilation. If indoor fan is off, dampers
will close. During Unoccupied mode operation, dampers will
remain closed unless a DCV demand is received.
When the room temperature calls for heat (W1 closes), the
heating controls are energized.
Table 12 — Economizer Module - Left Hand
Terminal Blocks
LABEL
TYPE
DESCRIPTION
Top Left Terminal Block
MAT
MAT
20k NTC
and COM
Mixed Air Temperature Sensor (Polarity
Insensitive Connection)
OAT
OAT
20k NTC
and COM
Outdoor Air Temperature Sensor
(Polarity Insensitive Connection)
S-BUS
S-BUS
S-BUS (Sylk
Bus)
Enthalpy Control Sensor
(Polarity Insensitive Connection)
Bottom Left Terminal Block
IAQ 2-10
2-10 vdc
Air Quality Sensor Input (e.g. CO
2
sensor)
IAQ COM
COM
Air Quality Sensor Common
IAQ 24V
24 vac
Air Quality Sensor 24 vac Source
ACT 2-10
2-10 vdc
Damper Actuator Output (2-10 vdc)
ACT COM
COM
Damper Actuator Output Common
ACT 24v
24 vac
Damper Actuator 24 vac Source
Table 13 — Economizer Module - Right Hand
Terminal Blocks
LABEL
TYPE
DESCRIPTION
Top Right Terminal Blocks
na
The first terminal is not used.
AUX2 I
24 vac IN
Shut Down (SD) or HEAT (W)
Conventional only
and
Heat Pump Changeover (O-B) in Heat
Pump mode.
OCC
24 vac IN
Occupied/Unoccupied Input
E-GND
E-GND
Earth Ground - System Required
EXH1
24 vac OUT Exhaust Fan 1 Output
AUX1 O
24 vac OUT
Programmable:
Exhaust fan 2 output
or
ERV
or
System alarm output
Bottom Right Terminal Blocks
Y2-I
24 vac IN
Y2 in - Cooling Stage 2 Input from
space thermostat
Y2-O
24 vac OUT Y2 out - Cooling Stage 2 Output to
stage 2 mechanical cooling
Y1-I
24 vac IN
Y1 in - Cooling Stage 2 Input from
space thermostat
Y1-O
24 vac OUT Y1 out - Cooling Stage 2 Output to
stage 2 mechanical cooling
C
COM
24 vac Common
R
24 vac
24 vac Power (hot)
