Lennox XC20-036-230-01 Installation And Service Procedure page 73

Table 18. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes
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
Inverter
Code
Alert Inverter
flashes)
Code
Codes
Red LED
E 433 29 2 flashes
E 434 53 5 flashes
E 435 60 6 flashes
E 436 62 6 flashes
E 437 65 6 flashes
E 438 73 7 flashes
®
®
or iComfort S30 thermostat.
LED Flash
(number of
Priority
Green LED
The inverter has detected a
Moderate
9 flashes compressor
/ Critical
condition.
Outdoor control has lost com­
munications with the inverter
for greater than 3 minutes.
Outdoor control will stop all
compressor demands, re­
Moderate / cycle power to the inverter by
3 flashes
Critical de-energizing the contactor
for 2 minutes. If this occurs 3
time in one thermostat call,
the outdoor unit will locked
out and display a critical
code.
Moderate
OFF Inverter internal error.
/ Critical
Inverter heat sink temperat­
ure exceeded limit. Occurs
when the heat sink temperat­
ure exceeds the inverter limit.
Inverter issues code 13 first,
then slows down to allow the
heat sink to cool. If temperat­
Moderate /
2 flashes ure remains high, outdoor
Critical
unit stops (compressor and
fan). Anti-short cycle is initi­
ated. If condition occurs 5
times within an hour, system
is locked out. To clear, dis­
connect power to outdoor
unit and restart.
Heat
sensor fault has occurred
Moderate
5 flashes (temperature less than 4 ºF or
/ Critical
greater than 264ºF after 10
minutes of operation).
The inverter has detected a
PFC over current condition.
This would be caused by a
high load condition, high
pressure, or outdoor fan fail­
ure. Outdoor control will dis­
play the code when the in­
Moderate / verter has the error. After 3
3 flashes
Critical minutes, the inverter will re­
set and the compressor will
turn on again. If it happens
10 times within a 60 minute
rolling time period, the OD
control will lock out operation
of the outdoor unit and dis­
play a critical code.
Alarm Description
Error occurs when compressor peak phase current is
greater than 28A. Inverter will issue code 14 first and slow
down to try to reduce the current. If the current remains
over-current high, outdoor unit will stop (compressor and fan).
Anti­short cycle is initiated. If condition occurs 5 times
within an hour, system will lock out. To clear disconnect
power to outdoor unit and restart.
Issues:
(1) Loose electrical connections.
(2) Interruption of main power to inverter.
Corrective Actions:
(1) Check all electrical connections.
(2) Check for proper main power to inverter.
When this error occurs, the outdoor control will cycle
power to the inverter by opening the contactor for 2
minutes. Check that the EEPROM is properly seated.
After power is cycled to the inverter 3 times, the outdoor
unit is locked out.
Issue: Feedback from supplier tear down of inverter in­
dicates that the screws that hold the inverter to the invert­
er board were loose causing poor contact between these
two components.
Corrective Action: Tighten screws that hold the heat
sink to the inverter control board.
NOTE: Wait five minutes to all capacitor to discharge be­
fore checking screws.
This occurs when the temperature sensor detects a tem­
sink temperature perature less than 0.4ºF or greater than 264ºF after 10
minutes of operation. If condition is detected, outdoor unit
will stop (compressor and fan). Anti­short cycle is initi­
ated. If condition occurs 5 times within an hour, system
will lock out. To clear disconnect power to outdoor unit
and restart. If problem persists, replace inverter.
Issue: Possible issue is system running at high pres­
sures. Check for high pressure trips or other alert codes in
room thermostat and outdoor control.
73
Possible Causes and Clearing Alarm
XC20