Page 53
SGH/SCH036, 060, 120, 240
Optional Economizer Settings
A-General
The economizer allows outdoor air to be used for free
cooling or ventilation requirements.
B-Configure Economizer
Use the following menu and go through the installation wizard.
SETUP > INSTALL
When prompted, set
Configuration ID 1
, position
2
to the
applicable economizer option. Economizer options are
shown in table 31. Once the option is set, the installation
wizard prompts will vary depending on the option selected.
Note - Some setup information is factory-set, such as the
unit model number. Verify that each setting is correct before
advancing to the next prompt.
Sensors are used to determine outdoor air suitability for free
cooling. Some economizer options require field-installed
sensors. See table 31. See figure 38 for sensor locations.
Use the following menu to make adjustments to the
economizer option once configured. Refer to the Menu
Interface tables in the Unit Controller Setup Guide
provided with this unit.
SETUP > TEST & BALANCE > DAMPER
TABLE 31
ECONOMIZER CONFIGURATION OPTIONS
Option
Description
Required
Sensors
Dampers will modulate to 55
°
F* (default) discharge air
when outdoor air is suitable:
Param
eter**
M
Motorized Out
door Air Dampers
None
Dampers do not modulate; dampers will open to minimum position during the occupied time
period and close during the unoccupied time period.
NA
T
ECON FRCL
TEMP OFFSET
Factory-
Installed
Outdoor air temperature (RT17) is less than return air temperature (RT16) by at least the OFF
SET value (10
°
F default).
161
ECON FREECL
TEMP SP
Factory-
Installed
Outdoor air temperature (RT17) is less than the free cooling setpoint (60
°
F default).
160
G
GLO
NA
Dampers will modulate to maintain 55
°
F* (default) discharge air when a 24VAC signal is pro
vided to the GLO input (P297-9). Global input also brings on the blower. Refer to Energy Man
agement System manufacturer's instructions for required sensors.
NA
S
ECON FREECL
ENTH SP
C7400
Outdoor air enthalpy (A7) is less than free cooling setpoint (73
°
F default).
162
D
ECN FRCL
ENTH OFFSET
(Two)
C7400
Outdoor air enthalpy (A7) is less than return air enthalpy (A62) by at least the OFFSET value.
163
*RT6 discharge air sensor is factory-installed. See parameter 159 in the Unit Controller Setup Guide.
**Refer to the Menu Interface tables in the Unit Controller Setup Guide provided with this unit.
FIGURE 38
SENSOR LOCATION
RT17
OUTDOOR AIR SENSOR
(10, 20-TON UNITS)
RT16
RETURN
AIR SENSOR
(ALL UNITS)
RT6
DISCHARGE
AIR SENSOR
(ALL UNITS)
RT17
OUTDOOR
AIR SENSOR
(3 & 5 TON UNITS)
20-TON
UNIT SHOWN
