Manual 2100-720E
Page
34 of 42
TABLE 12
Recommended Airflow
FIGURE 27
Speed Taps
Speed Tap 1: Vent Speed
Speed Tap 2: Balanced Climate Speed
Speed Tap 3: Default Speed
Speed Tap 4: Medium Speed
Speed Tap 5: High Speed
24VAC Common
24VAC "R"
signal through
thermostat output
Model
Nominal
Rated
CFM*
Nominal
Rated
ESP*
Recommended
Airflow Range
Factory
Speed
Connection
W3SAC
1150
.15
1050 - 1350
Default
W4SAC
1550
.20
1450 - 1750
Default
W5SAC
1750
.20
1650 - 2000
Default
* Rated CFM and ESP on factory speed connection.
Setting Unit Airflow
The unit is set from the factory at the default speed.
Most units have three selectable cooling speed taps that
can be utilized. The default speed is the lowest cooling
speed. The two higher speed taps can be used for higher
duct static applications so that the unit can maintain the
recommended airflow as shown in Table 12. The higher
speeds can also be used when higher sensible cooling is
desired. To change to the higher speed taps, move the
orange/black wire on the blower speed terminal block to
either MED or HI. Refer to Table 14 on page 38 for the
corresponding airflow of each tap. Set the unit duct static
based on the highest airflow that the unit will run at.
NOTE:
Be sure to adjust the system static or blower
speed to maintain airflows above the minimum
recommendations to prevent freeze up conditions
if Balanced Climate mode is activated.
Do not operate the unit in Balanced Climate mode
if running high static applications as indicated in
the blower performance table. If Balanced Climate
mode is activated as described on page 18, the unit
will run in this mode at all times unless there is a
call for ventilation, electric heat or 2nd stage cooling
from a 2-stage thermostat. At that time, the unit will
automatically activate a higher speed tap.
Blower Speeds
The ECM motor blower speeds are communicated
through 24VAC low voltage signals from the low voltage
terminal block inside the control panel area to speed
taps. Each speed tap is programmed by Bard at the
factory to different motor torque settings (see Figure 27).
Unit
Operation
Thermostat Inputs – 24VAC
Speed Taps
Blower Speed
Compressor
Operation
G
Y1
Y2
Y3 W1 W2
A
D
1
2
3-4-5
1
Blower Only
X
X
Vent/Blower Only
Off
Part Load Cool
X
X
X
X
Balanced Climate
On
Balanced Climate Cooling
3
X
X
X
X
X
Balanced Climate
On
Full Load Cool
X
X
X
X
X
X
X
Lo/Med/Hi
On
1st Stage Heat
X
X
Lo/Med/Hi
Off
2nd Stage Heat
X
X
X
Lo/Med/Hi
Off
Dehumidify
2
X
X
X
Balanced Climate
On
¹ Fan speed is selectable through the blower speed control terminal block. LO (default), MED or HI speeds can be used.
2
Dehumidification operation is disabled when a call for heating or cooling occurs. Unit runs at Balanced Climate speed
during dehumidification operation.
3
Y2-Y3 low voltage strip jumper must be removed.
TABLE 13
Blower Speeds for Unit Operational Modes
Five factory programmed speed taps (torque settings)
are available for the motor, and are selected through
different unit modes of operation. These modes are
energized by 24VAC signals from the low voltage
terminal block located inside the control panel by a
thermostat or other controlling device.
Multiple motor speed taps may be energized
simultaneously by 24VAC power during different modes
of operation. The highest number speed tap energized
takes priority with 5 being the highest and 1 being
the lowest. See Table 13 for the corresponding blower
speeds with the different modes of operation.
