Power Exhaust Operation - Lennox PRODIGY2.0 Application Manual

12. Power Exhaust Operation

The M3 unit controller is capable of controlling up to two stages of power exhaust. The M3 unit controller configuration has
to match the power exhaust equipment installed in the roof top unit:
To enable the Power Exhaust feature in the software, set Configuration ID 1 position 3 to either S or D (whichever is
applicable).
•
N ­ No power exhaust installed
•
S ­ Single stage power exhaust
•
D ­ Dual stage power exhaust.
To enable the Power Exhaust Control feature in the software, set Configuration ID 1 position 4 to A. See table 34 for
setting the applicable fresh air damper position for either single or two-stage exhaust operation.
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.
Table 34. Exhaust Control
Input
Fresh Air Damper Position
Input
Fresh Air Damper Position
Set Points (SP)
Parameter
215 50% Travel
Set points (SP)
Parameter
215 50% Travel
219 70% Travel
54
Dead-band (DB)
Default Parameter
216
Dead-band (DB)
Default Parameter
216
220
Default
20% Travel*
Default
20% Travel*
10% Travel