Lennox LGT Series Unit Information page 42

Free Cooling Free Cooling
Mode Set Point
TEMP OFFSET
TEMP OAT STPT
Remote Remote
ENTH DIFF OFFSET
ENTH ODE STPT
GLOBAL GLOBAL
*Enthalpy includes effects of both temperature and humidity.
**Energy management systems may require additional field-provided sensors; refer to manufacturer's instructions.
ECONOMIZER
FIGURE 33
TABLE 13
ECONOMIZER MODES AND SETPOINT
Field Provided Dampers will modulate to 55°F (default, parameter 159) discharge
Sensors
Outdoor air temperature (RT17) is less than return air temperature
None Needed (RT16) by at least the OFFSET value (10°F default; parameter
Outdoor air temperature (RT17) is less than the OAT STPT value
None Needed
Either of the TEMP modes can be used when a network OAS
signal is provided by an energy management or building control
Energy Management
system, via BACnet, LonTalk, or L Connection. The network can
System**
command OAS, NOT OAS, or AUTO. AUTO returns to local control
Outdoor air enthalpy* (A7) is less than return air enthalpy (A62)
(Two) C7400
by at least the OFFSET value (1mA = 2°F default; parameter 163).
Outdoor air enthalpy (A7) is less than free cooling setpoint (12mA
C7400
Global input is energized by (P297-9). This setting is also used for
outdoor air damper applications. Global input also brings on the
24VAC Input Signal blower. (This mode is NOT used when OAS signal is provided via
network connection. GLO is only used when a 24VAC signal is
ECONOMIZER
RETURN AIR
air (RT6) when outdoor air is suitable:
161).
(75°F default; parameter 160).
of OAS, which is the selected TEMP mode.
= 75°F default, parameter 162).
used to energize the P297-9 GLO input.)
Page 42
ACCESSORY
PANEL MULLION
DIVIDER PANEL
BOTTOM OF
COMPRESSOR
SECTION
FLANGED
OPENING
Input Ranges
0-40°F
41-75°F
NA
0mA-4mA
12-19mA
NA