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Table 21. 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
®
thermostat.
Alert
Codes
Code
Inverter LED Flash Code
(number of flashes)
Priority
Alarm Description
Possible Causes and Clearing Alarm
Red LED
Green LED
E 434
53
5 flashes
3 flashes
Moderate /
Critical
Outdoor control has lost
communications with the
inverter for greater than
3 minutes. Outdoor con
trol will stop all com
pressor demands, re
cycle power to the invert
er by 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.
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.
E 435
60
6 flashes
OFF
Moderate /
Critical
Inverter internal error.
When this error occurs, the outdoor control cycles
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
.
E 436
62
6 flashes
2 flashes
Moderate /
Critical
Inverter heat sink tem
perature exceeded limit.
Occurs when the heat
sink temperature ex
ceeds the inverter limit.
Inverter issues code 13
first, then slows down to
allow the heat sink to
cool. If temperature re
mains high, outdoor unit
stops (compressor and
fan). Anti-short cycle is
initiated. If condition oc
curs 5 times within an
hour, system is locked
out. To clear, disconnect
power to outdoor unit
and restart.
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 dis
charge before checking screws.
E 437
65
6 flashes
5 flashes
Moderate /
Critical
Heat sink temperature
sensor fault has occurred
(temperature less than 4
ºF or greater than 264ºF
after 10 minutes of opera
tion)
.
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 compressor and fan stop.
Antishort cycle is initiated. If condition occurs 5
times within an hour, system is locked out. To clear
disconnect power to outdoor unit and restart. If
problem persists, replace inverter.
E 438
73
7 flashes
3 flashes
Moderate /
Critical
The inverter has detec
ted a PFC over current
condition. This would be
caused by a high load
condition, high pressure,
or outdoor fan fail
ure. Outdoor control will
display the code when
the inverter has the er
ror. After 3 minutes, the
inverter will reset and
the compressor will turn
on again. If it happens
10 times within a 60
minute rolling time peri
od, the OD control will
lock out operation of the
outdoor unit and display
a critical code.
Issue
: Possible issue is system running at high
pressures. Check for high pressure trips or other
alert codes in room thermostat and outdoor control.
