Lennox EL23XCV Series Manual page 74

TABLE 20. 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/dehumidifi-
cation). 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 S30/S40 thermostat.
Inverter LED Flash
Code (number of
Alert Inverter
flashes)
Codes Code
Red LED
E 434 53 5 flashes
E 435 60 6 flashes
E 436 62 6 flashes
E 437 65 6 flashes
Priority Alarm Description
Green
LED
Outdoor control has lost
communications with the
inverter for greater than 3
minutes.
Outdoor unit will stop all
compressor demand.
Outdoor control will attempt
Moderate /
3 flashes
to establish communication
Critical
multiple times and will
automatically clear when
the error clears. Unit will
lock out after 60 minutes
if communication is not
established and will display
a critical error code.
Moderate /
OFF Inverter internal error.
Critical
Inverter heat sink
temperature exceeded
limit. Occurs when the
heat sink temperature
exceeds the inverter limit.
Inverter issues code 13
first, then slows down to
allow the heat sink to cool.
If temperature remains
high, outdoor unit stops
(compressor and fan).
Anti-short cycle is initiated.
Moderate /
If condition occurs 5 times
2 flashes
Critical
within an hour, system is
locked out.
To clear, disconnect
power to the indoor unit
(24VAC power source to
the outdoor control) which
will power off the outdoor
control and will open the
outdoor unit contactor,
which interrupts power to
the inverter and then re-
apply power.
Heat sink temperature
sensor fault has occurred
Moderate /
5 flashes (temperature less than 4 ºF
Critical
or greater than 264ºF after
10 minutes of operation).
Issues:
(1) Outdoor disconnect is off or outdoor power is off, when
indoor power is on (source for 24VAC)
(2) Loose electrical power connections
(3) Interruption of main power to the inverter
(4) Generator powers indoor unit, but not the outdoor unit.
Corrective Actions:
(1) To reset, cycle the indoor power off (source of 24VAC
to outdoor unit) and back on. This will de-energize
outdoor control and inverter by cycling the contactor.
(2) Make sure the disconnect is on
(3) Check electrical power supply connections
(4) Check for proper main 230V power supply
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 indicates
that the screws that hold the inverter to the inverter 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
before checking screws.
This occurs when the temperature sensor detects a
temperature 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 initiated.
If condition occurs 5 times within an hour, system will lock
out.
To clear, disconnect power to the indoor unit (24VAC
power source to the outdoor control) which will power
off the outdoor control and will open the outdoor unit
contactor, which interrupts power to the inverter and then
re-apply power.
Page 74
Possible Causes and Clearing Alarm