Discharge Air Control - Lennox Prodigy 2.0 Application Manual

10. Discharge Air Control

10.1. Cooling
The discharge air control cooling option automatically cycles up to 4-stages of cooling to maintain a discharge air control
cooling set point.
•
When an economizer is installed, adjust free cooling set point Parameter 159 approximately 2 degrees lower than
Discharge Air Control Cooling set point. This will allow free cooling to operate before Discharge Air Control Cooling
energizes compressors.
•
Refer to figure 13 for Discharge Air Control Cooling cooling stages.
•
Adjust Parameter 111 to option 4 to enable discharge air control cooling.
Discharge air sensor RT6 must be moved to the supply air duct, preferably after a 90 degree branch of the main duct.
Discharge Air Control Cooling is initiated by an input in one of three ways:
1. Y1 input from an external device— If the M3 Unit Controller is configured for wired thermostat.
Go to SETTINGS > CONTROL > CONTROL TYPE = WIRED THERMOSTAT.
2. Cooling demand while in RTU STANDALONE mode:
Go to SETUP > NETWORK INEGRATION > NETWORK = RTU STANDALONE > OCC BLOWER MODE = > BACK
UP MODE = > and continue to answer questions concerning heating and cooling setpoints.
3. Cooling demand while in room sensor mode:
Go to SETUP > NETWORK INEGRATION > NETWORK = (L CONNECTION, LONTALK OR BACNET) > any
additional network settings > CONTROL MODE = ROOM SENSOR > and continue to answer questions concerning
network sensor type, OCC blower mode and backup mode.
C1 = Cooling Stage 1
C2 = Cooling Stage 2
C3 = Cooling Stage 3
C4 = Cooling Stage 4
55°F Default Occupied
Discharge Air Control
Cooling Set point
Parameter
180
Figure 13. Discharge Air Control Cooling Stages - Default Values Shown
IMPORTANT
61
60
59
58
° °
55 F + 2 F Diff
Parameter 180 +
57
Parameter 185
ON
C2
56
55
ON
54 C1
53
55
OFF
52
Parameter 180 + Parameter
185 - Parameter 182
51
OFF
50
55°F - 5°F
Parameter 180 -
Parameter 182
Parameter 181 Unoccupied DACC_SP
Parameter 183 DAC Cooling Stage-Up Delay 3 minutes
Parameter 184 DAC Cooling Stage-Down Delay 2 minutes
Compressor Minimum Off or Run Times Apply
Page 49
° °
55 F + 6
Parameter 180 + (Para­
meter 185 X 3)
ON
C4
° °
55 F + 4 F Diff.
Parameter 180 + (Para­
meter 185 X 2)
ON
C3
OFF
Parameter 180 + (Parameter 185
X 3) - Parameter 182
° °
OFF 55 F + (2 F X 2) -5
Parameter 180 + ( Parameter
185 X 2) - Parameter 182
° ° °
F + 2 F - 5 F
5°F Discharge Air Cooling Control
Dead-band (All Stages Same Setting)
Parameter 182
F Diff.
° ° °
55 F + (2 F X 3) - 5 F
°
F