16
Table 14 — 45R Parallel Fan Powered Terminal Unit With PSC Fan Motor Performance
NOTES:
1. 45Q maximum primary airflow (CFM) is based on 1.00 in. wg differential
pressure signal from inlet airflow sensor.
2. Minimum recommended airflow (CFM) is based on 0.03 in. wg differential
pressure of the inlet airflow sensor, or 0 airflow. 0.03 in. wg is equal to 15%
to 20% of the nominal flow rating of the terminal. Less than 15% to 20%
may result in greater than +5% control of box flow.
3. 45R maximum/minimum fan airflow is based on 0.25 in. wg external (down-
stream) static pressure, respectively.
Speed Controller
Each Carrier fan powered air terminal unit is equipped with a
fan SCR speed controller, located on the bottom of the control
box. The SCR can be adjusted in the field.
NOTE: The 45J size 7 unit and 45Q size 4 unit have two SCR
speed controllers, one for each fan. One SCR is located in the
standard position at the bottom of the control box; the other is at
the top of the control box.
The fan airflow output is dependent on the setting of the con-
troller and the downstream static resistance.
TO INCREASE THE FAN SPEED (RPM), turn the slotted
adjustment on the controller clockwise toward the “HI” marking
printed on the controller face plate (see to Fig. 11).
TO DECREASE THE FAN SPEED (RPM), turn the adjustment
counterclockwise toward the “LO” marking. (see Fig. 11).
Fig. 11 — Fan Speed Controller
Setting Fan Air Flow with ECM Motors
Several terminal unit models are available with ECM motors for
easy balancing. These motors supply a determined amount of air
regardless of static pressure from ductwork layout or air distri-
bution. The ECM motors are programmed to provide a maxi-
mum CFM depending on model and unit size. The motors are
then set to provide the desired CFM as a proportional amount of
the maximum. The proportion can be set by several options:
VCU (CONTROL OPTION 6)
VCU controlled units are manually operated with a digital read-
out on the ECM controller (see Fig. 12). The digital readout pro-
vides a percent of maximum. A fan adjustment knob is rotated
until the desired percent is displayed. After 20 seconds from
final adjustment, the controller display will alternate between
percent and motor RPMs.
Fig. 12 — VCU ECM Controller
ACU-O, 0-10VDC (0-20MA) INPUT (CONTROL OPTION 7)
The board is factory set to accept a 0-10 Vdc signal to control
the airflow between 0% and 100% as shown in the chart in
Fig. 12. This option does not allow for on/off control. Setting
the jumper to the “Opt” position as shown in the “Jumper
Setting” in Fig. 13 sets the control signal to 0-10Vdc signal.
UNIT
SIZE
INLET SIZE (in.)
FAN AIRFLOW
PRIMARY AIRFLOW
MOTOR HP
MOTOR AMPS
MIN
MAX
MIN #
MAX
120V
208/240V
277V
2
6
350
665
52 or 0
515
1/6
3.7
1.5
1.4
8
92 or 0
916
10
143 or 0
1432
4
8
420
855
92 or 0
916
1/4
5.6
2.5
2.0
10
143 or 0
1432
13.5 x 8
206 or 0
2062
CAUTION
The minimum stop on the speed controller is factory set at
an internal minimum stop to prevent damage to the motor.
Do not attempt to override this minimum stop or electrical
damage to the fan motor may result.
LO
HI
U R
RANCO
MXF-544002-001
1005
33
-01
277 V 12L
5 FLA
50
6
Z