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W7212, W7213, W7214 ECONOMIZER LOGIC MODULES
7
63-2596—09
The logic module can operate as either a basic free cooling
controller, or it can incorporate additional functions. Table 3
details the input/output (I/O) logic of the module.
Table 3. W7212 Economizer I/O Logic.
NOTES:
—
Power Exhaust, DCV and Free Cooling have set-
points and LED indications.
—
For models with a B terminal (W7213):
No power to B: cooling mode, free cool enabled.
Module follows logic detailed above.
24V power to B: heating mode, free cool disabled.
Actuator drives to minimum position or DCV MAX
whichever is the higher of the two. When power is
cut to the economizer (fan is off) then the damper
will spring return closed.
—
For models with an O terminal (W7214):
24V power to O: cooling mode, free cool enabled.
Module follows logic detailed above.
No power to O: heating mode, free cool disabled.
Actuator drives to minimum position or DCV MAX
whichever is the higher of the two. When power is
cut to the economizer (fan is off) then the damper
will spring return closed.
INPUTS
OUTPUTS
Demand Control
Ventilation (DCV)
Enthalpy
a
Y1
Y2
Compressor
N Terminal
b
Outdoor
Return
Stage
1
Stage
2
Occupied
b
Unoccupied
b
Damper
Below set
(DCV LED Off)
See Table 1 for
outdoor damper
action if input on
AQ-AQ1 terminals
is 1Vdc or < 1Vdc.
This the fault for
CO2 sensor failure.
If no sensor or Vdc
input is added to
AQ-AQ1 terminals
then use the DCV
MAX potentiometer
to adjust the
minimum position.
High
(Free Cooling LED Off)
Low
On On On
On
Minimum position
Closed
On Off On
Off
Off Off Off
Off
Low
(Free Cooling LED On)
High
On On On
Off
Modulating
c
(between min. position
and full-open)
Modulating
c
(between closed and
full-open)
On Off Off
Off
Off Off Off
Off
Minimum position
Closed
Above set
(DCV LED On)
High
(Free Cooling LED Off)
Low
On On On
On
Modulating
d
(between min. position
and DCV maximum)
Modulating
d, g
(between closed and
DCV maximum)
On Off On
Off
Off Off Off
Off
Low
(Free Cooling LED On)
High
On On On
Off
Modulating
e
Modulating
f
On Off Off
Off
Off Off Off
Off
a
For single enthalpy control, the module compares outdoor enthalpy to the ABCD setpoint.
b
Power at N terminal determines Occupied/Unoccupied setting:
•W7212: 24 Vac (Occupied), no power (Unoccupied).
•W7213,W7214: No power (Occupied), 24 Vac (Unoccupied).
c
Modulation is based on the mixed air sensor signal.
d
Modulation is based on the DCV signal. If the CO2 sensor input (AQ-AQ1) terminals is < 1Vdc or the sensor has failed, the motor
will drive to MIN POS or DCV MAX which ever is highest.
e
Modulation is based on the greater of DCV and mixed air sensor signals, between minimum position and either
maximum position (DCV) or fully open (mixed air signal).
f
Modulation is based on the greater of DCV and mixed air sensor signals, between closed and either
maximum position (DCV) or fully open (mixed air signal).
g
Modulation is based on the DCV signal, if the CO2 sensor input (AQ-AQ1) terminals is < 1Vdc or the sensor has failed, the motor
will drive DCV MAX in the occupied mode. When power is cut to the economizer (fan is off) then the damper will spring return
closed.