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STEADY YELLOW “OUTDOOR
AIR SUITABLE” LED INDICATES
OUTDOOR AIR CAN BE USED
FOR COOLING
ECON DIP SWITCH
M2 UNIT CONTROLLER
0-100%
MINIMUM
POSITION
POTENTIOMETER
FIGURE 22
ECONOMIZER BOARD
Note-All economizer modes of operation, except DSET, will modulate dampers to 55°F (13°C) discharge air.
ODE (differential)
GLO
ODE (enthalpy)
Set to DIF
A
B
C
D
DIF
ENTH SET PNT
A
B
C
D
DIF
Set to A
ENTH SET PNT
TEMP
FIGURE 23
DIP SWITCHES
Outdoor Air Damper and Economizer Operation
DIRECT DRIVE AND BELT DRIVE SYSTEM OPERATION (3 THROUGH 6 TONS):
Note: Direct drive units feature ECM condenser fans that are staged to match the compressor's capacity. When the compres
sor is operating at first stage, the condenser fan is operating at low speed. The condenser fan switches to high speed when
the compressor switches to second stage to match operation.
Modulating Outdoor Air Damper:
Damper minimum positions #1 and 2 are adjusted during unit setup to provide minimum fresh air requirements at the indi
cated supply fan speeds per ASHRAE 62.1.
-Supply fan is off and the outdoor air damper is closed
-Supply fan is on low speed and the outdoor air damper is at minimum position 1
-Supply fan is on high speed and the outdoor air damper is at minimum position 2
1
Outdoor Air is Suitable
Note: When outdoor air is not suitable during the occupied time period, damper modulates to minimum position. When out
door air is not suitable during the unoccupied time period, damper modulates closed.
Cooling - Thermostat or Zone Sensor Mode (Up to 3 stages Y1, Y2, Y3)
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