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ERROR CODES:
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/dehumidi-
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.
Alert
Codes
Inverter
Code
Inverter LED Flash
Code (number of
ashes)
Priority Alarm Description Possible Causes and Clearing Alarm
Red LED
Green
LED
E 423 40 4 ashes OFF
Moderate /
Critical
The inverter has detected a
circuit problem.
Control will lock out after 10 strikes within an hour.
To clear, disconnect power to the indoor unit (24VAC
power source to the outdoor control) which will power
o the outdoor control and will open the outdoor unit
contactor, which interrupts power to the inverter and then
re-apply power.
E 426 N/A N/A N/A Critical Excessive inverter alarms
After ten faults within one hour, control will lock out.
Indicates poor system operation. Review history of alarms
to resolve system setup. Check condenser fan motor,
TXV, indoor unit blower motor, stuck reversing valve, over-
charge, undercharge, and clogged refrigerant lter.
To clear, disconnect power to the indoor unit (24VAC
power source to the outdoor control) which will power
o the outdoor control and will open the outdoor unit
contactor, which interrupts power to the inverter and then
re-apply power. Inverter alarms 12 to 14 and 53 do not
count towards this lock out condition.
E 427 21 2 ashes 1 ash
Moderate /
Critical
The inverter has detected a
DC peak fault condition.
If condition (55A or higher) is detected, outdoor unit will
stop (compressor and fan). Antishort cycle is initiated. If
peak current (55A or higher) occurs 10 times within an
hour, system will lock out.
Indicates high pressure, condenser fan failure, locked
compressor rotor or overcharge. To clear, disconnect
power to the indoor unit (24VAC power source to the
outdoor control) which will power o the outdoor control
and will open the outdoor unit contactor, which interrupts
power to the inverter and then re-apply power.
E 428 22 2 ashes 2 ashes
Moderate /
Critical
The inverter has detected
a high main input current
condition
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.
Indicates high pressure, condenser fan failure or
overcharge. To clear, disconnect power to the indoor unit
(24VAC power source to the outdoor control) which will
power o the outdoor control and will open the outdoor
unit contactor, which interrupts power to the inverter and
then re-apply power.
E 429 23 2 ashes 3 ashes
Moderate /
Critical
On a call for compressor
operation, if DC link power
in inverter does not rise
above 180 VDC for 2 and
3 ton models, 250 VDC for
4 and 5 ton models, within
30 seconds, the control will
display a moderate code.
If condition is detected,
outdoor unit will stop
(Compressor and fan).
Antishort cycles is initiated.
If condition occurs 10
times within a 60 minute
rolling time period, system
will lock out and display a
critical code.
Issues:
(1) If DC link power in inverter does not rise above 180
VDC for 2- and 3-ton models, 250 VDC for 4- and
5-ton models, within 30 seconds, the outdoor control
will display a moderate code.
(2) Capacitors on inverter do not properly charge.
Corrective Actions:
(1) Check for proper main power to outdoor unit and for
any loose electrical connections.
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