Lennox PRODIGY 2.0 Unit Controller

The S4 high pressure switch has opened due to high system pressure. The corresponding compressor is de-energized for a set delay.

The S7 high pressure switch has opened due to high system pressure. The corresponding compressor is de-energized for a set delay.

The S28 high pressure switch has opened due to high system pressure. The corresponding compressor is de-energized for a set delay.

The S96 high pressure switch has opened due to high system pressure. The corresponding compressor is de-energized for a set delay.

The inverter has detected a low-level issue affecting performance. This could be related to compressor current, heat sink temperature, or PFC input current. The system may automatically reduce compressor speed.

The inverter has detected a high-level issue, such as peak DC current, maximum current lockout, low DC link voltage, locked rotor, or high DC link voltage. The compressor will stop temporarily.

A critical inverter error has occurred, potentially due to issues like peak DC current, maximum current lockout, low/high DC link voltage, locked rotor, or compressor over current. This requires a manual reset.

The unit controller cannot communicate with the inverter. Compressor operation will be disabled until communication is restored.

There is a voltage mismatch between the inverter and the system. Compressor operation will be disabled.

A thermal protection switch has opened due to a temperature rise, de-energizing the compressor. The compressor is off.

A thermal protection switch has tripped three times in a single demand cycle, locking out compressor operation. This is due to repeated high pressure or high temperature conditions.

Setting Configuration ID 2, Position 4 to either '2' (for DI-2) or '3' (for DI-3) enables the M3 unit controller to monitor the blower overload relay switch (S42). This monitors current flow to the blower motor.

This alarm is displayed when an optional safety switch (like a blower overload, loss of phase protector, or supply duct high pressure limit switch) connected to the unit controller is open. This indicates a safety condition has been met, shutting down the unit.

The S49 freeze-stat switch has opened because the evaporator coil temperature dropped too low. The corresponding compressor is de-energized.

The S50 freeze-stat switch has opened because the evaporator coil temperature dropped too low. The corresponding compressor is de-energized.

The S53 freeze-stat switch has opened because the evaporator coil temperature dropped too low. The corresponding compressor is de-energized.

The S95 freeze-stat switch has opened because the evaporator coil temperature dropped too low. The corresponding compressor is de-energized.

This alarm is displayed when the return air temperature exceeds the limit set for heating mode. The alarm code is shown but not stored in memory for recall. Parameter 115 (HEAT RET AIR LIMIT) defines this limit.

This alarm is displayed when the return air temperature falls below the limit set for cooling mode. The alarm code is shown but not stored in memory for recall. Parameter 114 (COOL RET AIR LIMIT) defines this limit.

This error code indicates that the unit controller did not detect the gas valve being energized within two minutes after a heating demand was initiated for gas heat section 1.

This error code is displayed when the gas valve for gas heat section 1 is energized and then de-energized three times (default setting) during a single heating demand.

This alarm code is displayed when the gas valve for gas heat section 2 is energized and then de-energized three times (default setting) during a single heating demand.

This alarm code indicates that the unit controller did not detect the gas valve being energized within two minutes after a heating demand was initiated for gas heat section 2.

This alarm indicates an issue with the airflow switch, suggesting it's not detecting proper air movement. The display will show the alarm code, an alarming value, and a timestamp. More details can be found by pressing the HELP button.

This alarm code is triggered if the actual airflow is less than the target percentage (set by Parameter 234) for longer than the duration set by Parameter 235. This indicates insufficient airflow is being supplied.

This advanced airflow alarm is triggered if the RPM feedback of the blower is less than 50 RPM, indicating that no supply airflow is being generated.

This alarm is triggered when the damper actuator does not move the damper to the target position within the predefined time, meaning the control voltage does not match the feedback voltage within the acceptable tolerance.

This alarm is triggered when the actual outdoor air intake is less than the target outdoor air by a specified percentage (set by Parameter 239) for a prolonged period (set by Parameter 243).

This alarm is triggered when the actual outdoor air intake is greater than the target outdoor air percentage (set by Parameter 240) for a specified duration (set by Parameter 244).

These alarms are triggered if the S18 or S45 switches are not detected as closed within 30 seconds after the combustion air inducer starts. They can also trigger if these switches are sensed as open for three seconds while the unit is trying to heat.

These alarms indicate that a 'three-strikes' condition has occurred during a single heating demand. This typically relates to the number of times a specific switch (like the combustion air inducer switch) has failed to meet its required state.

The indoor blower is currently operating.

The indoor blower is operating, and the outdoor air is suitable for free cooling.

Setting Configuration ID 2, Position 2 to 'C' enables the M3 unit controller to monitor the dirty filter switch (S27). When the filter is dirty, S27 closes, and the controller will display and store an error code.

The system is operating in cooling mode, utilizing mechanical cooling along with maximum free cooling from the economizer with its damper fully open.

The system is operating in cooling mode, using mechanical cooling combined with variable free cooling from the economizer.

The unit controller reports an error code. The value range is 0 to 255, where a non-zero value indicates an error.

Setting Configuration ID 2, Position 1 to 'D' means the M3 unit controller will not monitor the air flow switch (S52). This is typically used when S52 is physically connected to a DDC controller instead.

A short delay is in progress, typically before the compressor starts after the outdoor fan is energized. This is normal operation for some models.

The system has cleared an alarm and is undergoing a standard five-minute delay before resuming normal operations.

A value of 0 for economizer error indicates that no error has been encountered by the economizer system.

The Heartbeat LED is flashing rapidly, indicating the unit is in bootloader or firmware update mode.

The Heartbeat LED is flashing slowly, indicating normal operation of the unit.

The Heartbeat LED is solid green, indicating the unit is in configuration or test mode, not normal operating mode.

The system is not currently receiving a signal for heating or cooling.

The system is not receiving a call for heating or cooling, and the outdoor air is suitable for free cooling.

The unit has shut down because one or more active alarms have been detected that require the system to halt operation. The specific alarm codes are displayed on the main system status screen.

Mechanical cooling is not currently allowed because the system is using free cooling. This occurs during specific conditions when outdoor air is suitable for cooling.

The unit has not been fully set up for operation. The installation menus need to be followed.

The red SERVICE LED is solid on, indicating the node is configured but no application is currently loaded or running.

The red SERVICE LED is flashing, indicating the node is not configured or an application has not been loaded.

The red SERVICE LED flashes quickly during initialization. This indicates messages are being passed to the M3 unit controller, which is normal operation.

The red SERVICE LED is consistently off, indicating the node is completely configured and ready for operation.

A smoke alarm has been detected through the unit's input sensors. The system may shut down or alter its operation.

The system is in a default start-up delay phase before servicing demands. Access the setup menu for installation.

The unit is currently in test mode. This may be for diagnostic purposes or network testing.