Honeywell C7400 Manual page 19

Demand Control
Ventilation (DCV) Outdoor
Below set (DCV High (Free
LED Off) Cooling LED Off)
Low (Free
Cooling LED On)
Above set (DCV High (Free
LED On) Cooling LED Off)
Low (Free
Cooling LED On)
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). W7212C returns to minimum position on CO
• 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.
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).
NOTES:
— DCV and Free Cooling have setpoints 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 (closed when Unoccupied).
— 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 (closed when Unoccupied).
SETTINGS AND
ADJUSTMENTS: W7212
CAUTION
Equipment Damage Hazard.
Excessive force can damage potentiometer
controls.
Use a small screwdriver when adjusting enthalpy
changeover and minimum damper position controls.
Table 5. W7212 Economizer I/O Logic.
INPUTS
a
Enthalpy
Return Y1
Low On
On
Off
High On
On
Off
Low On
On
Off
High On
On
Off
Compressor
Y2 Stage 1 Stage 2
On On On Minimum position
Off On Off
Off Off Off
On On Off
Modulating
min. position and full-
Off Off Off
open)
Off Off Off Minimum position
On On On
Modulating
min. position and DCV
Off On Off
maximum)
Off Off Off
On On Off
Modulating
Off Off Off
Off Off Off
Potentiometers with small screwdriver adjustment slots,
located on device face, provide adjustments for several
parameters (see Fig. 27 for locations on device):
— DCV setpoint.
— Minimum damper position.
— DCV maximum damper position.
— Enthalpy changeover.
— Exhaust setpoint.
19
SOLID STATE ECONOMIZER SYSTEM
OUTPUTS
b
N Terminal
b
Occupied Unoccupied
Damper
Closed
c
(between Modulating
closed and full-open)
Closed
d
(between Modulating
closed and DCV
maximum)
e
Modulating
sensor failure.
2
b
c
(between
d
(between
f
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