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2.1.2. Heating Stages
The M3 Unit Controller default thermostat operation is for two heating stages. See table 3 for gas heat units and table 4 for
electric heat units.
The M3 Unit Controller allows three different staging options:
Go to SETTINGS > RTU OPTION > EDIT PARAMETER =112 (HEAT STAGING OPTION)
Option 0. No heating operation
Option 1. Discharge Air Control with up to four stages. Discharge Air Control Heating (DACH) option automatically
cycles up to 4 stages of heating to maintain a discharge air temperature within specific tolerances of discharge air
control heating set point (occupied or unoccupied). See Parameters 174 and 175.
Option 2. Thermostat operation (default)
Table 3. Default Thermostat Mode Operation (Gas Heat)
No. of Heat Sections Gas Valve W1 Demand W2 Demand
1 (1) 1 Stage Gas Valve 1 Gas Valve 1
1 (1) 2 Stage Low Rate High Rate
2 (2) 1 Stage High Rate - Both Valves High Rate - Both Valves
2 (2) 2 Stage Low Rate - Both Valves High Rate - Both Valves
Table 4. Default Thermostat Mode Operation (Electric Heat)
No. of Heat Sections Stages Per Section W1 Demand W2 Demand
1 1 Stage 1 Stage 1
1 2 Stage 1 Stage 2
2 1 High Rate - Both Sections High Rate - Both Sections
2 2 Low Rate - Both Sections High Rate - Both Sections
2.2. System Mode - Room Sensor Backup Mode Set Points
This allows the M3 Unit Controller to use internal set points and input from a room sensor to operate the unit. An additional
thermostat or energy management system is not required.
2.2.1. Network Control Panel
The set points can also be adjusted using the optional network control panel (NPC). When a NCP is installed, the set points
are determined by the its schedule. The NPC communicates with the M3 Unit Controller via the L Connection network bus.
Internal M3 Unit Controller set points are used only if network communication is interrupted.
The room sensor is wired directly to each unit P298-6 and P298 -7 (marked GND and TMP on the Field Wiring Termination
Plugs). The room sensor wiring diagram key number is A2.
NOTE - To select either BACnet or LonTalk, Configuration ID 1, position 5 needs to be set to either B for BACnet or L for
LonTalk.
Internal set points can be adjusted using the user interface on the M3 Unit Controller. In room sensor mode, during the
occupied or unoccupied time period, the default M3 Unit Controller internal heating and cooling (occupied and unoccupied)
set points as reference in paragraph 2.2.3.
Use Parameter stage differential and deadband options to adjust set points in room sensor mode.
2.2.2. Room Sensor Back-Up Modes
Go to SETUP > NETWORK INTEGRATION wizard to configured a back up mode option. Use table 5 to follow the wizard
path to the backup mode setting.
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