Lennox KGC Series Unit Information page 44

A6 ENTHALPY CONTROLLER
2V
EXH
Open
2V
DCV
2V
Free
Cool
B
A
FREE COOLING SETPOINT;
A=Completely counterclockwise
D=Completely clockwise
FIGURE 33
A6 Enthalpy Control LEDs
A steady green Free Cool LED indicates that outdoor air is
suitable for free cooling.
When an optional IAQ sensor is installed, a steady green
DCV LED indicates that the IAQ reading is higher than
setpoint requiring more fresh air. See FIGURE 33.
Outdoor air is considered suitable when temperature and
humidity are less than the free cooling setpoints shown in
TABLE 22. Setting A is recommended. See FIGURE 33. At
setting A, free cooling will be energized when outdoor air
is approximately 73°F (23°C) and 50% relative humidity.
If indoor air is too warm or humid, lower the setpoint to B.
At setting B, free cooling will be energized at 70°F (21°C)
and 50% relative humidity.
When an optional A62 differential sensor is installed, turn
A6 enthalpy control free cooling setpoint potentiometer
completely clockwise to position "D".
EXH
Set
10V
MUM POSITION
Min
IAQ MAXIMUM
Pos
POSITION
(set higher than
DCV
minimum position)
Max
10V
IAQ READING IS
ABOVE SETPOINT
DCV
Set
10V
IAQ SETPOINT
OUTDOOR AIR
C
SUITABLE LED
D
ENTHALPY FREE COOLING SETPOINTS
Control Setting
A
B
C
D
*Setting A is recommended
Damper Minimum Position
NOTE - A jumper is factory-installed between TB1 R and
OC terminals to maintain occupied status (allowing min-
imum fresh air). When using an electronic thermostat or
energy management system with an occupied/unoccu-
pied feature, remove jumper.
1 - Set thermostat to occupied mode if the feature is
available. Make sure jumper is in place between
TB1 terminals R and OC if using a thermostat which
does not have the feature.
2 - Rotate MIN POS SET potentiometer to approximate
desired fresh air percentage.
NOTE - Damper minimum position can be set lower
than traditional minimum air requirements when
an IAQ sensor is specified. Dampers will open to
DCV MAX setting (if CO2 is above setpoint) to meet
traditional ventilation requirements.
3 - Measure outdoor air temperature. Mark the point on
the bottom line of chart 1 and label the point "A"
(40F, 4C shown).
4 - Measure return air temperature. Mark that point on
the top line of chart 1 (FIGURE 34) and label the
point "B" (74F, 23C shown).
5 - Measure mixed air (outdoor and return air)
temperature. Mark that point on the top line of chart
1 and label point "C" (70F, 21C shown).
6 - Draw a straight line between points A and B.
7 - Draw a vertical line through point C.
8 - Draw a horizontal line where the two lines meet.
Read the percent of fresh air intake on the side.
9 - If fresh air percentage is less than desired, adjust
MIN POS SET potentiometer higher. If fresh air
percentage is more than desired, adjust MIN POS
SET potentiometer lower. Repeat steps 3 through 8
until calculation reads desired fresh air percentage.
Page 44
TABLE 22
Enthalpy Setpoint At 50% RH
73° F (23° C)
70° F (21° C)
67° F (19° C)
63° F (17° C)