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.
Table 5. Alert Codes and Troubleshooting
Alert
Code
Priority
Alert Text
Steps to clear
407
Critical
(Outdoor Unit) The required amount of current is
not passing through run current transformer.
Required amount of current is not passing through Run current transformer. Clears the error after
current is sensed in RUN sensor, or 1 normal compressor run cycle, or after power reset
408
409
Critical
(Outdoor Unit) The compressor is running con-
tinuously.
Compressor runs continuously. Clears the error after 1 normal compressor run
cycle or after power reset.
Moderate
(Furnace / Air Handler / Outdoor Unit) The sec-
ondary voltage for the (furnace, air−handler or
outdoor unit) has fallen below 18VAC. If this
continues for 10 minutes, the thermostat will
turn off the (furnace, air−handler or outdoor unit).
Secondary voltage is below 18VAC. After 10 minutes, operation is discontinued.
Clears the code after voltage is higher than 20 VAC for 2 seconds or after power
reset.
410
411
Moderate
Critical
(Outdoor Unit) The outdoor unit pressure is be-
low the required limit.
Unit pressures are below the lower limit. Pressure switch opens at 40 psig (system shuts down) and
closes at 90 psig (system restarts).
(Outdoor Unit) The low pressure switch has
opened 5 times during one cooling cycle. As a
result, the thermostat has shutdown the outdoor
unit.
Open low pressure switch error count reached 5 strikes. Check system charge using approach and
sub cooling temperatures. Reset by putting outdoor unit control in test mode or resetting low voltage
power.
412
413
Moderate
Critical
(Outdoor Unit) The outdoor unit pressure is
above the required limit. The system will shut
down.
Unit pressure is above the upper limit. Pressure switch opens at 590 psig (system shuts down) and
closes at 418 psig (system restarts).
(Outdoor Unit) The high pressure switch has
opened 5 times during one cooling cycle. As a
result, the thermostat has shutdown the outdoor
unit.
Open high pressure switch error count reached 5 strikes. Check system charge
using approach and sub cooling temperatures. Check outdoor fan operation. Check for dirt or debris
blocking air flow to outdoor unit. Reset by putting outdoor unit control in test mode or resetting low
voltage power.
414
415
416
Critical
Critical
Critical
(Outdoor Unit) The discharge line temperature
is higher than the recommended upper limit of
279ºF.
Discharge line temperature is > 279ºF. Make sure coil is clean and airflow unobstructed in and out of
condenser. Check system operating pressures and compare to unit charging charts in installation
manual. Clears after discharge temperature is < 225ºF.
(Outdoor Unit) The discharge line temperature
has been consistently higher than the recom-
mended upper limit of 279ºF.
Discharge line high temperature error count reached 5 strikes. Make sure coil is clean and airflow
unobstructed in and out of condenser. Check system charge using approach and sub cooling tem-
peratures. Reset by putting outdoor board in test mode or resetting low voltage power.
(Outdoor Unit) The outdoor coil sensor is either
open, short−circuited or the temperature is out of
sensor range. As a result the outdoor unit con-
trol will not perform any defrost tempering.
Sensor being detected open or shorted, or temperature is out of sensor range.
Outdoor unit control will not perform demand or time/temperature defrost operation. (System will still
heat or cool.) Clears when outdoor unit control detects proper sensor readings.
417
Critical
(Outdoor Unit) The outdoor unit sensor is either
open, short−circuited or the temperature is out of
sensor range. As a result the outdoor unit con-
trol will not perform any defrost tempering.
Outdoor unit control detects open or shorted sensor, or temperature that is out of sensor range.
Critical Alert after 10 minutes. Reset by replacing sensor. This fault is detected by allowing the unit to
run for 90 seconds before checking sensor resistance. If the sensor resistance is not within range
after 90 seconds, the board will count one fault. After 5 faults, the board will lock out. Check for
proper sensor reading and attachment to line. Replace if out−of−specifications.
table continued on next page
icomfort Wi-Fiꢁ 7−Day Programmable Communicating Thermostat
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