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DCV Set and Max Settings
Adjust settings when an optional IAQ sensor is installed.
The DCV SET potentiometer is factory-set at approxi
mately 50% of the potentiometer range. Using a standard
1-2000ppm CO
2
sensor, dampers will start to open when
the IAQ sensor reads approximately 1000ppm. Adjust
the DCV SET potentiometer to the approximate setting
specified by the controls contractor. Refer to figure 20.
The DCV MAX potentiometer is factory-set at approxi
mately 50% of the potentiometer range or 6VDC. Damp
ers will open approximately half way when CO
2
rises
above setpoint. Adjust the DCV MAX potentiometer to
the approximate setting specified by the controls con
tractor. Refer to figure 20.
Note - DCV Max must be set higher than economizer mini
mum position setting for proper demand control ventilation.
Economizer Operation
The occupied time period is determined by the thermostat
or energy management system.
Outdoor Air Not Suitable:
During the unoccupied time period dampers are closed.
During the occupied time period a cooling demand will open
dampers to minimum position and mechanical cooling
functions normally.
During the occupied time period dampers will open to DCV
MAX when IAQ reading is above setpoint (regardless of
thermostat demand or outdoor air suitability).
Outdoor Air Suitable:
See table 9 for economizer operation with a standard two-
stage thermostat.
During the occupied period, dampers will open to DCV
MAX when IAQ reading is above setpoint (regardless of
thermostat demand or outdoor air suitability). DCV MAX will
NOT override damper full-open position. When an R1
mixed air sensor for modulating dampers is installed, DCV
MAX may override damper free cooling position when oc
cupancy is high and outdoor air temperatures are low. If R1
senses discharge air temperature below 45
_
F (7
_
C),
dampers will move to minimum position until discharge air
temperature rises to 48
_
F (9
_
C).
TABLE 9
ECONOMIZER OPERATION
- OUTDOOR AIR IS
SUITABLE
FOR FREE COOLING -- FREE COOL LED “ON”
ÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁ
THERMOSTAT DEMAND
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
DAMPER POSITION
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
MECHANICAL COOLING
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
UNOCCUPIED
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
OCCUPIED
ÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁ
OFF
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
CLOSED
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
CLOSED
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
NO
ÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁ
G
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
CLOSED
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
MINIMUM
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
NO
ÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁ
Y1
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
OPEN*
ÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁ
OPEN*
ÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
NO
ÁÁÁÁÁÁÁÁÁÁÁ
Y2
ÁÁÁÁÁÁÁÁÁ
OPEN*
ÁÁÁÁÁÁÁÁÁ
OPEN*
ÁÁÁÁÁÁÁÁÁÁ
STAGE 1
* Dampers will open to maintain 55°F (13°C) supply air when an R1 mixed air sensor is installed.
