Manual 2100-671
Page
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FIGURE 43
Economizer Setup – Enthalpy Control
FIGURE 42
Economizer Setup – Temp/Hum Control
FIGURE 41
Economizer Setup – Dry Bulb Control
27. Press UP or DOWN keys to adjust the outdoor dew
point setpoint for economizer operation to the
desired value.
28. Press ENTER key to save the value and scroll to
On
Diff
.
29. Press UP or DOWN keys to adjust the dew point
differential for which the economizer is re-enabled.
30. Press ENTER key to save the value.
31. Press ESCAPE key several times to return to Main
Menu screen.
See Table 6 for default settings for economizer operation.
When the economizer is activated during a free cooling
call only, using any of the previously mentioned modes,
a 0-10v analog signal will be sent to the economizer
actuator. The actuator will then open and close the
damper blades to maintain a mixed air temperature of
55°F. When the mixed air temperature increases, the
damper will open and when the mixed air temperature
decreases, the damper will close.
The economizer may be disabled by the LC if the
system determines it needs to enter dehumidification
mode. More information about the dehumidification
sequence can be found in the latest revision of LC6000
Service Instructions 2100-669. In addition to dehum
mode, the economizer may be disabled for 5 minutes
(adjustable) if the dust sensor indicates the outdoor
air may cause particulate buildup in the air filters.
After the time has expired and on a call for cooling,
the economizer will open again to sample the air. The
wall-mount unit will either return to normal operation
or remain locked out for another 5 minutes.
Economizer Operation – Minimum Position
The economizer has an option to set minimum position
for the economizer. The minimum position will only
be active while the blower is operating. To enable
minimum position all the time, continuous blower must
be activated for the wall unit in the LC6000. See latest
version of LC6000 Service Instructions 2100-669 for
continuous blower configuration.
TABLE 6
Economizer Default Settings
* In Enthalpy mode, outdoor temperature, humidity and calculated dew point are all considered for economizer operation.
Mode
Consideration
Economizer Available for Cooling
Economizer Not Available for Cooling
Temp
Only
Temp &
Humidity
Enthalpy*
Temperature
When the outdoor air temperature
is below 70°F
When the outdoor air temperature
is above 75°F
Humidity
When the outdoor humidity is below
80%
When the outdoor humidity is above
80%
Dew Point
When the outdoor dew point
is below 55°F
When the outdoor dew point
is above 60°F
