Variable-Capacity Inverter Control Operation, Checkout, Status / Error Codes; 2- And 3-Ton Unit Inverter View - Lennox XP25-024-230-01 Installation And Service Procedure

ERROR CODES:
Table 19. Outdoor Control 7-Segment Display Alert Codes - Outdoor Control Errors
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).
Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert
codes are also displayed on the iComfort Wi-Fi
Alert
Priority
Codes
The outdoor unit ambient temper­
ature sensor has malfunctioned.
E 180 Critical As a result the outdoor unit control
will not perform low ambient cool­
ing.
The outdoor coil sensor has mal­
Moderate/ functioned. As a result the out­
E 416
Critical
door unit control will not perform
defrost.
The liquid line temperature sensor
E 424 Moderate
has malfunctioned.

Variable-capacity Inverter Control Operation, Checkout, Status / Error Codes

OPERATION OF COMPONENTS:
Electromagnetic compatibility circuit (EMC): EMC ensures the correct operation of different equipment items which use or
respond to electromagnetic phenomena, and the avoidance of any interference effects.
NOTE - The 2- and 3-ton DC inverter control has the EMC built­in. The 4- and 5-ton units have an external EMC.
CONVERTER:
Converts AC (alternating current) to DC (direct current).
POWER FACTOR CORRECTION (PFC) CIRCUIT:
The PFC module is an integrated part of the outdoor DC inverter control that monitors the DC bus for high, low and abnormal
voltage conditions. If any of these conditions are detected, the PFC function and compressor will stop.
INTELLIGENT (INVERTER) POWER MODULE (IPM):
The IPM inverts DC voltage into AC voltage. The control method is known as pulse width modulation (PWM). This means the
DC is switched on and off very quickly (chopped) by the transistor switches to make simulated AC at required frequency and
voltage.
COMMUNICATION CONTROL CIRCUIT:
Receives and sends message between the DC inverter control and the outdoor control.
Power Factor Correction Circuit
Intelligent Power Module
®
thermostat.
Alarm Description
Converter
Figure 60. 2- and 3-Ton Unit Inverter
Possible Causes and Clearing Alarm
In normal operation, after outdoor control recognizes sensors, the alarm is sent if
valid temperature reading is lost. Compare outdoor sensor resistance to temperat­
ure/resistance charts in unit installation instructions. Replace sensor pack if neces­
sary. At the beginning of (any) configuration, furnace or air­handler control detects
the presence of the sensor(s). If detected (reading in range), appropriate feature is
®
shown in the iComfort Wi­Fi thermostat About screen. The alarm / fault clears upon
configuration, or when normal values are sensed.
Coil sensor being detected open or shorted, or temperature is out of coil sensor
range. Outdoor unit control will not perform demand or time/temperature defrost
operation. System is still able heat and cool. Check the resistance of the coil sensor
and compare to temperature resistance chart. Replace coil sensor if needed. The
alarm clears when outdoor unit control detects proper coil sensor readings or after a
power reset.
In normal operation, after outdoor control recognizes sensors, the alarm is sent if
valid temperature reading is lost. Compare liquid line sensor resistance to temperat­
ure/resistance charts in unit installation instructions. Replace sensor pack if neces­
sary. At the beginning of (any) configuration, furnace or air­handler control detects
the presence of the sensor(s). If detected (reading in range), appropriate feature is
®
shown in the iComfort Wi­Fi thermostat About screen. The alarm / fault clears upon
configuration, or when normal values are sensed.
Communication Control
Page 79
Electromagnetic Compatibility Circuits
XP25