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TABLE 29
MINIMUM AND MAXIMUM CFM
094U4E, 122U4E, 152U4E
Gas Heat Minimum CFM
Unit Gas Heat Size Airflow CFM*
LGH094-152 Std. , Med. 2225
LGH094-152 High 2550
Electric Heat Minimum CFM
Unit Heat Size (kW) Airflow CFM
LCH094 7.5 1750
LCH094 0, 15, 22.5, 30, 45 2750
LCH122, 152 15, 22.5, 30, 45 2750
LCH122, 152 0, 60 3500
Cooling Low Minimum CFM - 160 CFM/ton
Unit Blower Speed Airflow CFM
LGH/LCH094 Low 1200
LGH/LCH122 Low 1600
LGH/LCH152 Low 2000
Cooling High Minimum CFM - 220 CFM/ton
Unit Blower Speed Airflow CFM
LGH/LCH094 High 1650
LGH/LCH122 High 2200
LGH/LCH152 High 2750
Smoke and Ventilation Minimum CFM - 150 CFM/ton
Unit Not Applicable Airflow CFM
LGH/LCH094 NA 1125
LGH/LCH122 NA 1500
LGH/LCH152 NA 1875
Heating and Cooling Maximum CFM - 480 CFM/ton
Unit Blower Speed Airflow CFM
LGH/LCH094 High 3600
LGH/LCH122 High 4800
LGH/LCH152 High 6000
*Rounded to nearest 25 CFM.
X-Staged Supply Air Operation
This is a summary of cooling operation for both belt and di
rect drive blowers.
Note - During a dehumidification demand the blower oper
ates at the highest speed. Free cooling is locked-out during
reheat operation. Refer to Hot Gas Reheat start-up and op
eration section for details.
A-Two-Stage Thermostat
1-Economizer With Outdoor Air Suitable
Y1 Demand -
Compressors Off
Blower Cooling Low
Dampers modulate
Y2 Demand -
Compressors Off
Blower Cooling High
Dampers Modulate
Note - If dampers are at maximum open for three minutes,
compressor 1 is energized and blower stays on cooling
high.
2-No Economizer or Outdoor Air Not Suitable
Y1 Demand -
Compressor 1 On (on ultra high efficiency units,
one compressor will operate)
Blower Cooling Low
Dampers Minimum Position
Y2 Demand -
Compressor 1 and 2 On
Blower Cooling High
Dampers Minimum Position
B-Three-Stage Thermostat OR Zone Sensor
1-Economizer With Outdoor Air Suitable
Y1 Demand -
Compressors Off
Blower Cooling Low
Dampers modulate
Y2 Demand -
Compressors Off
Blower Cooling High
Dampers Modulate
Note - If dampers are at maximum open for three minutes,
compressor 1 is energized and blower stays on cooling high.
Y3 Demand -
Compressors 1 and 2 On
Blower Cooling High
Dampers Maximum Open
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