20
Supply Fan (Direct-Drive)
All 40RF units have the EcoBlue™ direct drive vane axial fan
system. The fan is driven by an ECM motor with speed that is
user set through the Unit Control Board (UCB). Speeds are ful-
ly configurable from 40% to 100% of motor’s maximum
speed. See Fig. 21 and 22.
EVALUATING MOTOR SPEED
The direct drive ECM blower motor uses a constant speed de-
sign. Motor speed is controlled by a 0-10Vdc signal, where
10Vdc is equal to motor’s maximum RPM.
Fig. 21 — Direct-Drive Supply Fan Assembly
SELECTING FAN SPEED
All units come factory-set for the corresponding voltage at
400 CFM per ton and either 1.2 in. wg (medium static units) or
2 in. wg (high static units) of external static pressure specific to
each unit. Fan speed should be set per job specification CFM
(cubic feet per minute) and ESP (external static pressure) re-
quired and per Fan Speed Set Up label mounted on the control
box. In some cases, the Fan Speed Set Up label may already in-
clude the field setting if unit was previously installed. Check
the box on the lower half of the label to see if the field voltage
setting was filled in and if so, set fan speed to that voltage. Oth-
erwise see detailed instructions below.
NOTE: Fan Speed Set-Up is for full load airflow. If the unit has
multiple stages of cooling, low cool and ventilation may operate at
lower fan rpms. This offset is factory set and controlled by the
UCB. If fan speed verification is being done with a strobe, fan
speed should be verified in all unit operation modes.
Units with Electro-mechanical controls
The Fan Speed set up controls are located on the lower section of
the Unit Control Board (UCB). See Fig. 23 for location.
1. Check the job specifications for the CFM (cubic feet per
minute) and ESP (external static pressure) required.
2. Using the chart on the Fan Speed Set Up labels (see
Fig. 24), calculate the Vdc from the CFM and ESP for the
base unit.
3. If installing any accessories listed at the bottom of the Set
Up Label, add accessory Vdc to base unit Vdc in upper
portion of label. For electric heaters use only one adder.
(ex. 2 stage heater uses only 2 stage adder, not 1 stage plus
2 stage).
NOTE: The Fan Speed Set Up labels are located on the Control
Box.
4. Connect a multimeter to the Vdc terminals on the UCB.
5. Set the Range Switch to either A, B, or C per the Switch
Range table.
6. Using a straight blade screwdriver turn the Vdc control
dial to fine tune the Vdc reading.
7. Record the reading in the Field Setting field.
Fig. 22 — ECM Motor Plug Connectors
CAUTION
UNIT OPERATION HAZARD
Failure to follow this caution could cause equipment damage.
Increasing fan speed produces a greater load on motor.
Do not exceed rated capacity of motor.
1
4
7
2
5
8
3
6
9
10 11 12
WHITE CTL Signal Common
BLACK
YELLOW
Power L1
Power L2
BLUE
ORANGE
GRAY Power L3
10vdc Source
0-10vdc Signal
YEL/GRN Earth Ground
RED
VIOLET
Safety Relay
PWM Signal
PINK
RED
Serial (R/T)
Safety Relay
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