iComfort Wi-Fi
®
7-Day Programmable Communicating Thermostat
Page 31
Table 10. Alert Codes and Troubleshooting
Critical alerts are displayed on Home (user) screen, in the Homeowner alert button, and in the
Installer alert button. Minor and Moderate alerts are found only in the Installer alert button.
Alert
Code
Steps to clear
Alert Text
Priority
424
Moderate
The liquid line temperature sensor has
malfunctioned.
In normal operation after outdoor control recognizes sensors, the alarm will be sent if valid
temperature reading is lost. Compare liquid line sensor resistance to temperature/resistance
charts in unit installation instructions. Replace sensor pack if necessary. At the beginning of
(any) configuration, furnace or airhandler control will detect the presence of the sensor(s). If
detected (reading in range), appropriate feature will be set as 'installed' and shown in the
iComfort WiFi
®
thermostat 'About' screen. The alarm / fault will clear upon configuration, or
sensing normal values.
425
Minor
Outdoor control has increased minimum
compressor speed to allow for proper oil
return due to low ambient temperature.
Outdoor ambient temperature is below system limit. Control will attempt to run at lowest al
lowed compressor speed to allow for proper oil return. Automatically clears when outdoor am
bient temperature rises above limit for more then 5 minutes.
426
Critical
Excessive inverter alarms
After ten faults within one hour control will lockout. To clear disconnect power to outdoor unit
and restart. Inverter alarms 12 to 14 and 53 do not count towards this lockout condition.
427
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). Anti-short
cycle is initiated. If peak current (55A or higher) occurs 10 times within an hour, system will
lockout. To clear, disconnect power to outdoor unit and restart.
428
Moderate /
Critical
The inverter has detected a high main input
current condition
.
If condition is detected, outdoor unit will stop (compressor and fan). Anti-short cycle is initi
ated. If condition occurs 10 times within an hour, system will lockout. To clear, disconnect
power to outdoor unit and restart.
429
Moderate /
Critical
The inverter has detected a DC link low
voltage condition
.
Error occurs when DC link voltage drops below 14VDC. If condition is detected, outdoor unit
will stop (compressor and fan). Anti-short cycle is initiated. If condition occurs 10 times within
an hour, system will lockout. To clear, disconnect power to outdoor unit and restart.
430
Moderate /
Critical
Compressor start-up failure
If condition is detected, outdoor unit will stop (compressor and fan). Anti-short cycle is initi
ated. If condition occurs 10 times within an hour, system will lockout. To clear, disconnect
power to outdoor unit and restart.
431
Moderate /
Critical
The inverter has detected a PFC circuit
over-current condition
.
Error occurs when PFC detects a over current condition of 100A peak. If condition is detected,
outdoor unit will stop (compressor and fan). Anti-short cycle is initiated. If condition occurs 10
times within an hour, system will lockout. To clear, disconnect power to outdoor unit and re
start.
432
Moderate /
Critical
The inverter has detected a DC link high
voltage condition.
Error occurs when the DC link capacitor voltage is greater than 480VDC. If condition is detec
ted, outdoor unit will stop (compressor and fan). Anti-short cycle is initiated. If condition occurs
10 times within an hour, system will lockout. System will stop. To clear, disconnect power to
outdoor unit and restart.
433
Moderate /
Critical
Compressor phase current is too high.
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 high, outdoor
unit will stop (compressor and fan). Antishort cycle is initiated. If condition occurs 5 times
within an hour, system will lockout. To clear disconnect power to outdoor unit and restart.
434
Moderate /
Critical
Outdoor control has lost communications
with the inverter for greater than 3 minutes.
This error will occur when communication checksum error occurs for 3 minutes. Outdoor con
trol will stop all compressor demands, recycle power to the inverter by deenergizing the con
tactor for 2 minutes.
435
Moderate /
Critical
Inverter internal error.
When this error occurs, the outdoor control will cycle power to the inverter by opening the con
tactor for 2 minutes. Outdoor
control will cycle power to the inverter 3 times and then outdoor
unit is locked out
.
436
Moderate /
Critical
Inverter heat sink temperature exceeded
limit
.
This occurs when the heat sink temperature exceeds the inverter limit. Inverter will issue code
13 first and slow down to try to cool the heat since. If temperature remains high, outdoor unit
will stop (compressor and fan). Antishort cycle is initiated. If condition occurs 5 times within
an hour, system will lockout. System will stop. To clear, disconnect power to outdoor unit and
restart.
437
Moderate /
Critical
Heat sink temperature sensor fault has
occurred (temperature less than 4 ºF or
greater than 264ºF after 10 minutes of
operation)
.
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 (com
pressor and fan). Antishort cycle is initiated. If condition occurs 5 times within an hour, system
will lockout. To clear disconnect power to outdoor unit and restart.
438
Moderate /
Critical
The inverter has detected a PFC circuit
over-current condition
.
Error occurs when PFC detects an input over current condition of 35A peak. If condition is
detected, outdoor unit will stop (compressor and fan). Anti-short cycle is initiated. If condition
occurs 10 times within an hour, system will lockout. To clear, disconnect power to outdoor unit
and restart.
439
Moderate
Compressor slowdown due to high input
current.
Input current is approaching a high limit. Compressor speed will automatically slow down. The
control continues sending the inverter speed demanded by the thermostat. The control will set
indoor CFM and outdoor RPM to values according to demand percentage rather than the actu
al Hz. Alarm is automatically clear.
440
Moderate
Compressor slowdown due to high heatsink
temperature.
Heat sink temperature is approaching limit. The compressor speed will automatically slow
down to reduce heatsink temperature. The control will set indoor CFM and outdoor RPM to
values according to demand percentage rather than the actual Hz. Alarm is automatically
cleared.
441
Moderate
Compressor
slowdown
due
to
high
compressor current.
Compressor current is approaching high limit. The compressor speed will automatically slow
down. The control will set indoor CFM and outdoor RPM to values according to demand per
centage rather than the actual Hz. Alarm is automatically cleared.
table continued on next page
