Main Controller Operation - Lennox Prodigy M2 Application Manual

2. Main Controller Operation

2.1. System Mode − Thermostat
The M2 will operate the unit from a thermostat, zone sensor, or the zoning system based on the System Mode selected in
ECTO 6.01. The default System Mode (option 0) is the thermostat mode.
DDC applications use thermostat mode for two or three−stage cooling and two−stage heating.
Units are shipped from the factory in system mode 0, Thermostat Mode. The M2 will operate two stages of heating and
cooling based on the thermostat Y1, Y2, W1, W2, G, and OCP (occupied) demands.
2.1.1. Cooling Stages
The M2 allows three different staging options; adjust ECTO 5.04 to select the option.
S
Option 1. Two Cooling Stages: Y2 demand brings on all mechanical stages of cooling during economizer operation.
S
Option 2. (Default) Two Cooling Stages: Cooling operation is shown in table 1. Y2 demand brings 1/2 or 2/3 mechani-
cal stages of cooling during economizer operation.
S
Option 3. Three Cooling Stages: Cooling operation is shown in table 2; this option requires the use of a three−stage
cool thermostat and a K27 relay. See wiring pictorial in figure 2 and wiring diagram control C section.
TO PROVIDE THREE COMPRESSOR STAGES.
REQUIRES 3 HEAT, 3 COOL THERMOSTAT AND K27 RELAY.
2.1.2. Heating Stages
The M2 default thermostat operation is for two heating stages. See table 3 for gas heat units, table 4 for electric heat units,
and table 5 for heat pump units.
Table 1. Thermostat Mode Operation Default (Two Cooling Stages ECTO 5.04 Option 2)
Number of Number of
Compressors
1
2
3
4
CP1 = Compressor 1, CP2 = Compressor 2, CP3 = Compressor 3, CP4 = Compressor 4.
(1)
− ECTO 5.04 option 1 will bring on all available mechanical cooling. *Assumes outdoor air is suitable for cooling.
Table 2. Thermostat Mode Operation (Three Cooling Stages ECTO 5.04 Option 3)
Number of Number of
Compressors
1
2
3
4
CP1 = Compressor 1, CP2 = Compressor 2, CP3 = Compressor 3, CP4 = Compressor 4. *Assumes outdoor air is suitable for cooling.
No. of Heat Sections
1
1
2
2
Figure 2. 3−stage cool (ECTO 5.04 opt. 3) wiring
No Economizer
Y1 Demand Y2 Demand Adds
CP1 CP1
CP1 CP2
CP1 + CP2 CP3
CP1 + CP2 CP3 + CP4
No Economizer
Y1 Demand Y2 Demand Adds
CP1 CP1
CP1 CP2
CP1 CP2
CP1 + CP2 CP3
Table 3. Default Thermostat Mode Operation (Gas Heat)
Gas Valve
(1) 1 Stage
(1) 2 Stage
(2) 1 Stage
(2) 2 Stage
Y3
A
Y2
Y1
B
A2
Y1 Demand
Free Cool
Free Cool
Free Cool
Free Cool
Y3 Demand Adds Y1 Demand
CP1 Free Cool
CP2 Free Cool
CP3 Free Cool
CP4 Free Cool
W1 Demand
Gas Valve 1
Low Rate
High Rate − Both Valves
Low Rate − Both Valves
Page 7
2. Main Controller Operation
J297A
7
K27−1
6
7 1
2
With Economizer
Y2 Demand Adds
CP1
(1)
CP1
(1)
CP1 + CP2
(1)
CP1 + CP2
With Economizer
Y2 Demand Adds Y3 Demand Adds
CP1 CP1
CP1 CP2
CP1 CP2
CP1 + CP2 CP3
W2 Demand
Gas Valve 1
High Rate
High Rate − Both Valves
High Rate − Both Valves
PRODIGYT M2 UNIT CONTROLLER