Lennox LGM Series Manual page 50

Note - Intake air CFM can also be determined using the out­
door air temperature, return air temperature and mixed air
temperature. Refer to the economizer or outdoor air
damper installation instructions.
Set Minimum Position 2
Use the same menu in the Unit Controller to set "Min OCP
Blwr High" for the blower CFM above the "midpoint" CFM.
When navigating into this menu, the Unit Controller will
bring on the corresponding blower speed and allow damper
position adjustment.
SETTINGS > RTU OPTIONS > DAMPER > MIN
DAMPER POSITION BLOWER ON HIGH = X.X %
Measure the intake air CFM. If the CFM is lower than the
design specified CFM for ventilation air, use the Unit Con­
troller to increase the damper percent open. If the CFM is
higher than specified, decrease the damper percent open.
Note - Intake air CFM can also be determined using the out­
door air temperature, return air temperature and mixed air
temperature. Refer to the economizer or outdoor air
damper installation instructions.
MINIMUM AND MAXIMUM CFM
Gas Heat Minimum CFM
Unit
LGM092/150
LGM092/150
Electric Heat Minimum CFM
Unit
LCM092
LCM092
LCM120, 150
LCM120, 150
Cooling Low Minimum CFM - 160 CFM/ton
Unit
LGM/LCM092
LGM/LCM120
LGM/LCM150
Cooling High Minimum CFM - 220 CFM/ton
Unit
LGM/LCM092
LGM/LCM120
LGM/LCM150
Smoke and Ventilation Minimum CFM - 150 CFM/ton
Unit
LGM/LCM092
LGM/LCM120
LGM/LCM150
Heating and Cooling Maximum CFM - 480 CFM/ton
Unit
LGM/LCM092
LGM/LCH120
LGM/LCH150
*Rounded to nearest 25 CFM.
Page 50
TABLE 24
Gas Heat Size
Std. , Med.
High
Heat Size (kW)
Airflow CFM
7.5
0, 15, 22.5, 30, 45
15, 22.5, 30, 45
0, 60
Blower Speed
Airflow CFM
Low
Low
Low
Blower Speed
Airflow CFM
High
High
High
Not Applicable
Airflow CFM
NA
NA
NA
Blower Speed
Airflow CFM
High
High
High
Airflow
CFM*
2225
2550
1750
2750
2750
3500
1200
1600
2000
1650
2200
2750
1125
1500
1875
3600
4800
6000