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F
C
100
OUTDOOR AIR IS SUITABLE FOR FREE COOLING -- FREE COOL LED "ON
THERMOSTAT DEMAND
OFF
G
Y1
Y2
*Dampers will modulate to maintain 55F (13C) supply air when an R1 mixed air sensor is installed
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 cool-
ing functions normally.
During the occupied time period dampers will open to
DCV MAX when IAQ reading is above setpoint (regard-
less of thermostat demand or outdoor air suitability)
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
C
-29
-23
-18
-12
-7
ECONOMIZER OPERATION
UNOCCUPIED
CLOSED
CLOSED
OPEN*
OPEN*
CHART 1
30
40
50
60
70
-1
4
10
16
21
C
A
30
40
50
60
70
-1
4
10
16
21
TABLE 14
DAMPER POSITION
OCCUPIED
CLOSED
MINIMUM
OPEN*
OPEN*
Outdoor Air Suitable:
See table 14 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 full-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).
Page 48
80
90
100
F
27
32
38
C
0
B
10
20
30
40
50
60
70
80
90
100
80
90
100
F
27
32
38
C
MECHANICAL COOLING
NO
NO
NO
STAGE 1
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