Trane DX - Sensible Heating Mode; Ventilation Only Mode

SYS-APG001A-EN Dedicated Outdoor Air Systems: Trane DX Outdoor Air Unit 15
Control of the Dedicated OA Unit
Sensible heating mode
If the outdoor air dew point is lower than, or equal to, the Dehumidification
Enable Setpoint, and the outdoor air dry-bulb temperature is lower than the
Heating Enable Setpoint, the unit operates in the Sensible Heating Mode
(Figure 12). In this mode, heater capacity is staged/modulated to warm the
outdoor air (OA) to the desired leaving-air dry-bulb temperature (CA).
Figure 12. Sensible heating mode
Ventilation only mode
If the outdoor air dew point is lower than, or equal to, the Dehumidification
Enable Setpoint, and the outdoor air dry-bulb temperature is lower than the
Cooling Enable Setpoint but warmer than the Heating Enable Setpoint, the
unit operates in the Ventilation Only Mode. In this mode, the fan continues to
operate, but both the compressors and heater are turned off.
CA
sensible cooling
30 35 40 45
50
55 65 70 80 90 100 11075 85 95 105
30
35
40
45
50
55
65
70
80
75
85
60
60
wet-bulb temperature, °F
dry-bulb temperature, °F
humidity ratio, grains/lb of dry air
0
20
40
60
80
100
120
140
160
180
dew-point temperature, °F
40
45
50
55
65
70
80
75
60
30
20
0
OA