Lennox PRODIGY M2 User Manual

3. Unit Component Operation
Page 13
PRODIGYT M2 UNIT CONTROLLER
3.3.3. Zone Sensor Mode
The occupied time period is controlled by the optional NCP when installed. The A55_P297−8 input is ignored while in the zone
sensor mode except during back−up operation.
3.3.4. Gas and Electric Heat Warm−Up Mode (During occupied time period)
Many building codes require a percentage of fresh outdoor air when a conditioned space is occupied. A 24 vac input at unit
A55_P297−8 energizes the occupied" (usually daytime) time period. A field−provided and −installed thermostat or energy
management system provides the input.
The first 60 minutes (default) of the first heating demand of the occupied time period is called the warm−up mode".
During the warm−up mode the M2 keeps economizer dampers closed to conserve energy. (ECTO 2.01, 3.01).
The warm−up mode may be bypassed by pressing the left pushbutton of the display until "CLR DLY" is seen.
3.3.5. Heat Pump Warm−Up Mode
The default M2 setting allows supplemental heat to be used during warm−up mode. Supplemental heat may be locked out during
warm−up mode for energy savings in two different ways. See the Electronic Configure to Order Control Parameters section to
lock out supplemental heat during warm−up. ECTO 1.01, 1.17.
3.3.6. Cool−Down Mode (During occupied time period)
To conserve energy, the M2 ignores second−stage cooling demand and the economizer opens the first 30 minutes (default) OR
one cooling cycle (whichever happens first) when the occupied time period starts. The cool−down mode applies only when out-
door air is suitable for free cooling. ECTO 4.01.
The cool−down mode may be bypassed by pressing the left pushbutton of the display until "CLR DLY" is seen.
3.3.7. Air Flow Switch (S52−Optional)
The air flow switch closes during normal unit operation. If air flow is interrupted 16 seconds after blower demand, S52 opens
and the M2 de−energizes the compressor, gas valves, electric heat, and closes economizer damper. The service alarm
output will turn on.
3.3.8. Dirty Filter Switch (S27−Optional)
The dirty filter switch is open during normal unit operation. A dirty filter will close S27 and the M2 will display and store the
error code and turn on the service alarm output.
3.4. Gas Heat OperationGas Units
The M2 has gas heat output control for up to two gas heat burners with two−stage gas valves. A first−stage heat demand ener-
gizes the gas valve low fire and a second−stage heat demand energizes the high fire. On units that have two heat sections, a
first−stage heat demand energizes low fire on both gas valves and a second−stage heat demand energizes high fire on both gas
valves.
3.5. Electric Heat OperationElectric / Electric Units
3.5.1. Electric Heat Operation
First−stage heating demand energizes first−stage electric heat (K15 and K17). Second−stage heating demand energizes
second−stage electric heat (K16 and K18). When first−stage and second−stage heating demands are simultaneous, a
12−second delay will occur between stage one and stage two (ECTO 2.05).
3.5.2. Primary or Secondary Limits
If an electric heat limit (S15 or S63) opens, electric heat is de−energized.
If an electric heat limit opens three times during a thermostat cycle, the service alarm output will turn on (ECTO 2.04).
3.6. Heat Pump Operation
3.6.1. Heat Operation
First−stage heating demand energizes compressor(s) for first−stage heating. Second−stage heating demand energizes sup-
plemental electric heat via K15, K16, K17, and K18 electric heat contactors. K15 and K17 are energized immediately; K16
and K18 are energized after a 12−second delay (ECTO 1.05).
3.6.2. Primary or Secondary Limits
If an electric heat limit (S15 or S63) opens, electric heat is de−energized.
If an electric heat limit opens five times during a thermostat cycle, the service alarm output will turn on (ECTO 1.04).
3.6.3. Defrost Cycle
Defrost is initiated when the defrost temperature switch (S6 or S9) closes. Defrost terminates either when defrost pressure
switch (S46 or S104) opens or when 15 minutes (default) has elapsed. (ECTO 1.16). The defrost cycle is not terminated
when a thermostat demand ends. Only one defrost cycle is allowed for every 60 minutes (default) of run time. (ECTO 1.15).

Lennox PRODIGY M2 Specifications

General

Brand	Lennox
Model	PRODIGY M2
Category	Controller
Language	English