![background image](http://html1.mh-extra.com/html/bard/d25a2pa/d25a2pa_installation-and-service-instructions-manual_3947242032.webp)
Manual 2100-643C
Page
32 of 59
OUTDOOR FAN MOTOR
Due to design considerations of the condenser section
of the wall-mount unit, placement/clearance of the
motor/fan blade is critical to heat dispersal. Should a
change of motor or fan blade be necessary, please view
Figure 2.6 for proper clearance adjustment.
DIRTY FILTER SWITCH
Located inside the blower compartment, this switch
measures air pressure differential across the filter (see
Figure 2.7). Manual reset only. Default setting: 0.8"
static, 50% blocked filter (approximately).
INDOOR BLOWER MOTOR
Unlike most other system fan motors, this motor is a
48VDC motor, and is very specialized in application.
Please see Table 2.4 (blower table).
PHOENIX ISOLATION RELAY:
WALL-MOUNT UNIT
Green DIN-Rail mount isolation relay used in the wall-
mount unit to isolate/filter 48VDC power, motor speed
signal and ground from the control board: Phoenix Mini
MCR-Style.
ZETTLER ISOLATION RELAYS:
WALL-MOUNT UNIT
Black Zettler surface mount relays used in the wall-
mount unit to isolate the start signal from:
• Power loss relay circuit (see Figure 2.8)
• High pressure relay circuit (see Figure 2.9)
• Blower motor start signal relay circuit (see Figure
2.10)
Model
Dimension A
All covered by
this manual
1.75"
FIGURE 2.6
Fan Blade Setting
"A"
AIRFLOW
MIS-1724
TABLE 2.4
Indoor Blower Performance
MODEL
RATED
ESP
MAX
ESP
FREE COOLING
CFM ABOVE 40°
FREE COOLING
CFM BELOW 40°
RATED
FULL LOAD
COOLING CFM
ELECTRIC
HEAT
AIRFLOW
D25A/D25L
0.15
0.50
1500
800
800
1100
D28A/D28L
0.10
0.50
1800
800
1100
1800
D35A/D35L
0.15
0.50
1500
800
1100
1100
D36A/D36L
0.15
0.50
1800
800
1100
1800
D42A/D42L
0.20
0.50
1800
950
1250
1800
D48A/D48L
0.20
0.50
1800
1100
1600
1800
D60A/D60L
0.20
0.50
1800
1100
1600
1800
LC Series controller derives at this decision point and switches the indoor motor speed. The damper actuator will then
adjust to still yield a 55°F supply air temperature.
FIGURE 2.7
Dirty Filter Switch