Lennox icomfort Wi-Fi - Page 32

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Table 1. 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 clearAlert TextPriority
421 Critical
Air Handler / Equipment Interface Module).
The heat pump defrost cycle has taken more
than 20 minutes to complete.
Voltage sensed on W output terminal when Y1 out is deactivated.
422 Moderate
Compressor top cap switch exceeding
thermal limit.
Check condenser fan motor, TXV, indoor unit blower motor, stuck reversing valve or
clogged refrigerant filter. Automatically clears when error is corrected.
423
Moderate /
Critical
The inverter has detected a circuit problem.
Control will lockout after 10 strikes within an hour. To clear disconnect power to outdoor
unit and restart.
424 Moderate
The liquid line temperature sensor has mal
functioned.
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/resist
ance charts in unit installation instructions. Replace sensor pack if necessary. At the be
ginning of (any) configuration, furnace or airhandler 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 WiFi
®
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 re
turn due to low ambient temperature.
Outdoor ambient temperature is below system limit. Control will attempt to run at lowest
allowed compressor speed to allow for proper oil return. Automatically clears when out
door ambient 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 condi
tion.
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
initiated. If condition occurs 10 times within an hour, system will lockout. To clear, discon
nect 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
initiated. If condition occurs 10 times within an hour, system will lockout. To clear, discon
nect power to outdoor unit and restart.