L Connection Network Back-Up Mode Requirements; Heating And Cooling Stages In Room Sensor Mode; Energence Lc/Lg -036 Through -074U (Ultra-High Efficiency Units) - Lennox PRODIGY2.0 Application Manual

2.2.4.

L Connection Network Back-Up Mode Requirements

Go to SETUP > NETWORK INTEGRATION wizard to configure a back up mode option. Table 10 references the
wizard path to the backup mode setting.
NETWORK NETWORK =
INTEGRATION L-CONNECTION
Back-up mode option is used when the communication link has been lost on the L Connection
after communication is interrupted, the M3 unit controller will start using the configured back-up mode and applicable set
points. The M3 unit controller will default to back-up set points for occupied heat or cool modes.
During normal room sensor operation with a Network Control Panel, the occupied demands are sent over the network
and the occupied input on P297-8 is ignored. The occupied input on P297­8 is only read if the network communication link
is lost and the back­up mode is set to Local Thermostat.
Room sensor mode will have a default of occupied. If communication is lost the system will remain in the last state it
received until communication is restored or power is cycled. At this point after the delays the units should go to a occupied
back up mode regardless of any input at P297­8 which will be ignored.
2.2.5.

Heating and Cooling Stages in Room Sensor Mode

In Room Sensor Mode default operation, the M3 unit controller controls up to 4-stages of heating and 4-stages of cooling.
See figure 4 and the parameters table.
The number of stages utilized depends on the type of equipment and whether or not an economizer is used. On units with
economizers, free cooling becomes stage 1 and all compressor stages shift up one stage. On units with four (4)
compressors and an economizer, compressors 3 and 4 are controlled together for stage 4.
2.2.5.1.

Energence LC/LG -036 through -074U (Ultra-High Efficiency Units)

The reference models features a fully variable compressor, indoor blower and outdoor fan. For cooling, the M3 unit
controller actively monitors space temperature from the room sensor and discharge air temperature. Based on this
information, the M3 unit controller modulates the indoor blower to meet the space temperature set point and modulates
the compressor to meet the discharge air temperature set point. The outdoor fan is controlled based on compressor
speed. In this way, the unit controller uses only the capacity needed to meet the space temperature and discharge air
temperature set points which improves unit efficiency, reliability, and comfort. Due to the variability of the compressor and
indoor blower, there are infinitely many stages of cooling depending on the set points and load in the space, which differs
from traditional commercial rooftop HVAC units that have fixed stages of cooling. The unit controller will cease unit
operation in cooling mode once the cooling demand in the space has been satisfied.
If the outdoor air is suitable and the unit features an economizer, instead of using mechanical cooling to meet a low
cooling demand, the M3 unit controller will try to meet the demand by opening the economizer and using outdoor air. The
economizer damper will modulate to maintain Parameter 159 setting (supply air temperature) and satisfy the cooling
demand.
If the unit is unable to satisfy the cooling demand using outdoor air, then the unit will react to the high cooling demand by
initiating mechanical cooling while keeping the economizer at the fully open position. The unit controller will modulate
mechanical cooling capacity based on the cooling load until the cooling demand has been satisfied.
Table 10. Menu Interface (Level 1 - SETUP)
LCONN ADDRESS = X
•
•
•
•
CONTROL MODE =
ROOM SENSOR,
•
MONITOR ONLY OR
NETWORK
THERMOSTAT
•
•
•
•
13
NETWORK SENSOR CO2 = YES OR NO
NETWORK SENSOR RELATIVE HUMIDITY = YES OR NO
NETWORK SENSOR TEMPEATURE = YES OR NO
ROOM SENSOR OCC BLOWER MODE= AUTO CYCLES OR ON-
CONTINUOUS 1, 2 OR 3 *
BACKUP MODE = NONE, ROOM SENSOR, RETURN AIR BACKUP
OR THERMOSTAT
BACKUP SETPOINTS OCCUPIED HEAT = XX.X F
BACKUP SETPOINTS UNOCCUPIED HEAT = XX.X F
BACKUP SETPOINTS OCCUPIED COOL = XX.X F
BACKUP SETPOINTS UNOCCUPIED COOL = XX.X F
®
system bus. Five minutes