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The Unit Controller will calculate the “midpoint” CFM.
Set Minimum Position 1
Use the following menu in the Unit Controller to set “Min
OCP Blwr Low” for the blower CFM below 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 > EDIT PARAMETER >
ENTER DATA ID - 9 > MIN DAMPER LOW BLOWER =
X.X %
Measure the intake air CFM. If the CFM is lower than the
design specified CFM for ventilation air, use the Unit
Controller 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
outdoor 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
Controller 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
outdoor air temperature, return air temperature and mixed
air temperature. Refer to the economizer or outdoor air
damper installation instructions.
TABLE 27
MINIMUM AND MAXIMUM CFM
DIRECT DRIVE BLOWERS
036 & 060
Gas Heat Minimum CFM
Unit
Gas Heat Size
Airflow CFM*
SG 036, 060
Std.
1175
SG 036
Med.
1475
SG 060
Med.
1500
SG 060
High
1625
Electric Heat Minimum CFM
Unit
Heat Size (kW)
Airflow CFM
SC 036
0, 10, 15
1025
SC 060
0, 10, 15, 20, 30
1650
Cooling Low Minimum - CFM
Unit
Blower Speed
Airflow CFM
SG/SC 036
Low
600
SG/SC 060
Low
750
Cooling High Minimum - CFM
Unit
Blower Speed
Airflow CFM
SG/SC 036
High
600
SG/SC 060
High
750
Smoke and Ventilation Minimum - CFM
Unit
Blower Speed
Airflow CFM
SG/SC 036
High
600
SG/SC 060
High
750
Cooling Maximum CFM - 480 CFM/ton
Unit
Blower Speed
Airflow CFM
SG/SC 036
High
1450
SG/SC 060
High
2400
Electric Heat Maximum CFM
Unit
Blower Speed
Airflow CFM
SC 036
High
1450
SC 060
High
2400
Gas Heat Maximum CFM
Unit
Gas Heat Size
Airflow CFM
SG 036
Std.
1450
SG 036
Med.
1475
SG 060
Std., Med., High
2400
*Rounded to nearest 25 CFM.
