Power Exhaust Operation - Lennox Prodigy 2.0 Application Manual

7.11.4.1. Set Point Control Option
Set point control mode is commonly used in areas with high occupancy and frequent change out such as classrooms or
conference rooms.
In applications requiring this on/off damper response to carbon dioxide levels, set the start open (Parameter 118 - DCV
DAMP START OPEN) set point higher than the full open (Parameter 119 - DCV DAMP FULL OPEN) set point. The dampers
will drive to fully-open position immediately. Figure 11 shows the set point control option.
Change Parameters 122 and 123 to set the minimum outdoor temperature limits. Change Parameters 120 and 121 to set
the maximum temperature limits.
Mixed air temperatures less than 45°F (7°C) on units with an aluminized heat exchanger or less than 30°F (-1°C) on
stainless steel heat exchangers will void the manufacturer's warranty.
7.11.4.2. Determining Indoor Air Quality Inputs
Go to DATA> IN/OUTPUTS > SENSORS menu selection from the M3 Unit Controller menu display.

8. Power Exhaust Operation

The M3 Controller is capable of controlling up to two stages of power exhaust. The M3 configuration has to match the power
exhaust equipment installed in the roof top unit:
Configuration ID 1 position 3 needs to be set to one of the following options::
N ­ No power exhaust installed
S ­ Single stage power exhaust
D ­ Dual stage power exhaust.
To enable power exhaust control Configuration ID 1 position 4 needs to be set to A for enabling damper position control.
See table 33 for further details.
Single-Stage Exhaust
Enabled when
Blower is energized.
A55_P265-12 output energizes the first stage exhaust relay when the fresh air damper position reaches 50% Travel (Parameter 215) when the
blower is operating. The exhaust will de-energize when the damper position decreases 20% (Parameter 216) less than the set point or when the
blower is de-energized.
Two-Stage Exhaust
Enabled when
Blower is energized.
* Indicates to check unit parameter label as default may be altered at factory test.
100
Parameter 117
Max. Open
Min. Position
carbon dioxide (ppm)
Figure 11. Set point Control Indoor Air Quality Option
Table 33. Exhaust Control
Input
Fresh Air Damper Position
Input
Fresh Air Damper Position
IMPORTANT
Close Open
Parameter 119 Parameter 118
(full) (start)
Set Points (SP)
Parameter
215
Set points (SP)
Parameter
215
219
Page 43
Dead-band (DB)
Default Parameter
50% Travel 216
Dead-band (DB)
Default Parameter
50% Travel 216
70% Travel 220
Default
20% Travel*
Default
20% Travel*
10% Travel