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28. Events and Alarms
28.1. Phase - Voltage Detection
The M3 unit controller has the ability to detect that the rooftop unit power source has the correct frequency, phasing and
voltage levels. When this feature is enabled, the detection of frequency and phasing is determined at power-on and the
voltage level is continuously monitored. If any of these is out of range, then an alarm is logged and the rooftop unit
operation is locked out.
1. Alarms Detected at Power-On Start up:
121 - LINE FREQ DOES NOT MATCH UNIT CONFIG
126 - LINE PHASING DOES NOT MATCH UNIT CONFIG
2. Alarms - Continuously Monitoring
122 - 24VAC PRMARY VOLTAGE LOW
123 - 24VAC PRIMARY VOLTAGE HIGH
134 - 24VAC SECONDARY VOLTAGE LOW
125 - 24VAC SECONDARY VOLTAGE HIGH
Alarms 122 through 125 are auto-resetting. The rooftop operation will be restored five (5) minutes after the proper voltage
levels are restored. Alarms 121 and 126 requires removing the power and correcting the issue before restoring the
rooftop operation
The frequency (60 or 50 Hz) and the phasing (single or three-phase) of the power source is determined by the model
number stored in the M3 unit controller. This model number and enabling/disabling the Phase-Voltage Detection feature
can be modified through the M3 unit controller user interface. See the Installation and Setup Guide for instructions on how
to configure the CONFIGURATION ID 2, Position 5. Options are:
N = NOT INSTALLED
1 = ENABLED INTERNAL (LENNOX)
2 = EXTERNAL (A42) PHASE DETECTION ON DI-2
3 = EXTERNAL (A42) PHASE DETECTION ON DI-3
When an event occurs, the M3 unit controller will display a code which corresponds to control function. Error codes are
stored and can be recalled later. See the
Installation & Setup Guide For The Prodigy M3 unit controller
for information
about viewing and silencing the alarms via the user interface.
NOTE:
Any references in the user interface referencing Advanced Airflow actually indicates Smart Airflow
®
.
Service Relays
Selected alarms (marked with * in table result in the closure of the service relay contacts (DO1). The contacts remain
closed until the Prodigy resets, or alarm condition is cleared AND alarm status is read via explicit SBUS command
.
Other
modes of operation may be selected and are described in the Prodigy Application Guide (Advanced Features).
28.2. M3 Unit Controller Alarm and Event Codes
Table 65. Prodigy 2.0 Alarm and Event Codes
Selected alarms (marked with * in table result in the closure of the service relay contacts (DO1).
ALARM
CODE
DISPLAY MESSAGE
EVENT ACTION
1
LOSS OF POWER DETECTION (SINGLE
PHASE UNITS)
Check power connections.
The M3 unit controller will set an alarm “Erratic Power” whenever service is turned
off due to detection of power loss. User will be able to clear “Erratic Power” alarm via
user interface. The M3 unit controller will clear “Power Erratic” after the
Compressor
Min OFF Delay
has expired. If compressor demand is still present the M3 unit con
troller will restart compressor(s) after the
Compressor Min OFF Delay
has expired.
2 - 3 RESERVED
4*
SMOKE DETECTOR INPUT (A173)
A173 input is sensed as closed. Will automatically clears once input is detected
open. For smoke mode, check for source of smoke. While Smoke Alarm is active,
the M3 unit controller will not service any cooling, heating or ventilation demands.
5*
BLOWER S52
Unit off. Air flow switch is normally closed. Monitoring starts 16 seconds after blower
is started. if air flow switch is detected open after 16 second delay period, all com
pressors are de-energized, gas valves closed, electric heat turned off, economizer
damper closed, and blower is stopped. Alarm will automatically clear once the error
timed off delay has expired and system will resume. Check blower operation.
6*
DIRTY FILTER SWITCH S27
Dirty filter switch is detected as closed and will automatically clear once switch is
detected open. Replace filter or check filter switch S27.
