Figure 2.2 Wall-Mount Unit Control Board - Bard W48A2PQ Installation And Service Instructions Manual

3. If after 2 minutes, the low pressure switch is
still open, or opens again immediately aftward,
the board will delay for 2 minutes again (soft
lockout).
4. On the 3rd attempt, the board will lock out the
compressor and outdoor fan until manually reset.
• High Temperature 2 Alarm – Should the shelter
controller see 90°F, both free-cooling dampers will
open (regardless of outdoor temperature) to cool
the building.
Common/Control Ground
2-10VDC Free-Cooling Damper Signal
24VAC from Transformer
24VAC Output to Motor Start Relay
24VAC Heating Stg2 Output to Limit Switch
24VAC Heating Stg1 Output to Limit Switch
FIGURE 2.2
Wall-Mount Unit Control Board
Dirty Filter Switch
High Pressure Alarm Relay
Low Pressure Switch
Air Proving Switch
Damper Blade Switch
Common
+24VAC Power Input
• Smoke Alarm – Should the smoke detector send
an alarm signal to the controller, all blower,
compressor and ventilations functions cease.
• Freezestat – If coil temperature below 30°F is
sensed by the freezestat, the compressor will
deactivate for 5 minutes, or until the sensor sees
55°F, whichever comes first.
24V to OA Humidity Sensor
Ground
Freezestat Sensor 10kΩ
Outdoor Air Humidity Sensor 4-20mA
Return Air Temp Sensor 10kΩ
Outdoor Air Temp Sensor 10kΩ
Mixed Air Temp Sensor 10kΩ
+ Communication Wire
+24VAC Power Input
24VAC Cooling Output to Compressor Control Module
+24VAC from Transformer
–24VAC from Transformer
– Communication Wire
Manual 2100-642
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