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507124-04 3/2016
Four-Compressor Units:
Y1 Demand -
Compressors 1 and 2 On
180U, 240U - Two Compressors On
(one from each circuit)
Blower Cooling Low
Y2 Demand -
Compressors 1, 2 and 3 On
180U & 240U, any three compressors are On
Blower Cooling Medium
Y3 Demand -
All Compressors On
Blower Cooling High
C-Zone Sensor (4 Clg. Stages), 4-Compressor Units
1-Economizer With Outdoor Air Suitable
Y1 Demand -
Compressors Off
Blower Cooling Low
Dampers modulate
Y2 Demand -
Compressors Off
Blower Cooling High
Dampers Modulate
156, 180H, 210, 240H, 300S - If dampers are at
maximum open for three minutes, compressor 1 is
energized and blower stays on cooling high.
180U, 240U - If dampers are at maximum open for three
minutes, two compressors (one from each circuit) are
energized and blower stays on cooling high.
Y3 Demand -
Compressors 1 and 2 On
180U, 240U - Two Compressors On
(one from each circuit)
Blower Cooling High
Dampers Maximum Open
Y4 Demand -
All Compressors On
Blower Cooling High
Dampers Maximum Open
2-No Economizer or Outdoor Air Not Suitable
Y1 Demand -
Compressor 1 On
180U, 240U - Two Compressors On
(one from each circuit)
Blower Cooling Low
Y2 Demand -
Compressors 1 and 2 On
180U, 240U - Two Compressors On
(one from each circuit)
Blower Cooling Medium Low
Y3 Demand -
Compressors 1, 2 and 3 On
180U & 240U, any three compressors are On
Blower Cooling Medium High
Y4 Demand -
All Compressors On
Blower Cooling High
