Figure 2.5 Free Cooling Damper Operation - Bard W48A2PQ Installation And Service Instructions Manual

Free cooling can take place providing the outside air meets three (3) separate criteria:
1. The dewpoint must be below 60°F
2. The relative humidity must be below 80%
3. The outside air must be cooler than the current setpoint.
With an accurate psychrometer, it is easy to pinpoint when the damper should be
open or closed during normal operations.
TABLE 2.2
Controller Default Settings
Description
Temperature at local remote
(main) sensor
Temperature Setpoint
Heating Setpoint
Temperature High Limit –
Level 1
Temperature High Limit –
Level 2 (High Temp Alarm)
Temperature Low Limit
Cooling Stage Differential
Heating Stage Differential
Comfort Mode Setpoint
Comfort Mode Operation
Time
Freecooling Setpoint
Lead/Lag Changeover Time
(Active/Standby Rotation)
Temperature Units
Manual 2100-642
Page 42 of 82
FIGURE 2.5
Free Cooling Damper Operation
Below 80% Relative Humidity
Below 60°F Dewpoint
Default Setpoint
--
77°F
60°F
85°F
90°F
45°F
5°F
2°F
72°F
60 Minutes
55°F
1
°F