507341-01
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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 clear
Alert Text
Priority
406
Critical
(Outdoor Unit) The required amount of cur
rent is not passing through the start current
transformer.
Required amount of current is not passing through Start current transformer. Clears the
error after current is sensed in START sensor, or after power reset.
407
Critical
(Outdoor Unit) The required amount of cur
rent is not passing through run current trans
former.
Required amount of current is not passing through the
RUN
current transformer. Clears
the error after current is sensed in the
RUN
sensor, or 1 normal compressor run cycle, or
after power reset
408
Critical
(Outdoor Unit) The compressor is running
continuously.
Compressor runs continuously. Clears the error after 1 normal compressor run cycle or
after power reset.
409
Moderate
(Furnace / Air Handler / Outdoor Unit) The
secondary voltage for the
(furnace, airhand
ler or outdoor unit)
has fallen below 18VAC.
If this continues for 10 minutes, the thermo
stat will turn off the
(furnace, airhandler or
outdoor unit).
Secondary voltage is below 18VAC. After 10 minutes, operation is discontinued. Clears the
code after voltage is higher than 20VAC for two seconds or after power reset.
410
Moderate
(Outdoor Unit) The outdoor unit pressure is
below the required limit.
Low pressure switch opens at at a specific pressure (system shuts down) and
closes at a specific pressure (system restarts). For specific unit low pressure
values, see the applicable unit documentation.
411
Critical
(Outdoor Unit) The low pressure switch has
opened 5 times during a single demand. As
a result, the thermostat has shutdown the
outdoor unit.
Open low pressure switch error count reached five 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
Moderate
(Outdoor Unit) The outdoor unit pressure is
above the required limit. The system will
shut down.
Unit pressure is above the upper limit. System is shut down. Confirm that the system is
properly charged with refrigerant. Check condenser fan motor, TXV, indoor unit blower
motor, stuck reversing valve or clogged refrigerant filter. Confirm that the outdoor unit is
clean. The alarm clears after the pressure switch closes or a power reset
413
Critical
(Outdoor Unit) The high pressure switch has
opened 5 times during a single demand. 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
Critical
(Outdoor Unit) The discharge line temperat
ure 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.
