Lennox KGC Series Unit Information page 45

F
C
100
DCV Set and Max Settings
Adjust settings when an optional IAQ sensor is
installed. The DCV SET potentiometer is factory-set at
approximately 50% of the potentiometer range. Using a
standard 1-2000ppm CO2 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 33. The DCV MAX potentiometer is factory-set at
approximately 50% of the potentiometer range or 6VDC.
Dampers will open approximately halfway when CO2 rises
above setpoint. Adjust the DCV MAX potentiometer to the
approximate setting specified by the controls contractor.
Refer to FIGURE 33.
NOTE - DCV Max must be set higher than economizer
minimum position setting for proper demand control ven-
tilation.
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. See TABLE 24.
CALCULATE MINIMUM FRESH AIR PERCENTAGE
MIXED AND RETURN AIR TEMPERATURE
-20 -10 0 10 20
-29 -23 -18 -12 -7
0
10
20
30
40
50
60
70
80
90
-20 -10 0 10 20
F
-29 -23 -18 -12 -7
C
OUTDOOR AIR TEMPERATURE
CHART 1
30 40 50 60 70 80
-1 4 10 16 21 27
C B
A
30 40 50 60 70 80
-1 4 10 16 21 27
FIGURE 34
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 23 for economizer operation with a standard
twostage 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 fully open position. When an R1
mixed air sensor for modulating dampers is installed, DCV
MAX may override damper free cooling position when
occupancy is high and outdoor air temperatures are low.
If R1 senses discharge air temperature below 45F (7C),
dampers will move to minimum position until discharge air
temperature rises to 48F (9C).
Remove jumper R and OC when unit is controlled
with a thermostat that has a night setback mode. If
reheat operation is desired during tjhis time, wire
A20 to R.
Page 45
90 100
F
32 38
C
0
10
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30
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80
90
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90 100
F
32 38
C
IMPORTANT