49-5000400 Rev. 1
9
On Board Diagnostics
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Minimum Off Time:
To minimize short cycling, after the compressor shuts
off, it cannot restart until 3 minutes have passed.
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Freeze-up Prevention:
In COOLING Mode, the display will flash a snowflake
symbol to indicate the coil is freezing. The compressor
will not operate in this mode. To troubleshoot, it is
recommended to increase airflow by cleaning the filter
and opening the vents.
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Low Voltage Detection:
If the 12VDC drops below 10.5, the thermostat will
switch to “OFF” mode and the display will show “Lo”.
When voltage exceeds 10.5V, the display will cease
to show “Lo” , remain in “OFF” mode and other modes
must be reselected by the user.
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Heat Pump Lockout:
In HEAT PUMP Mode, if the outdoor temperature
drops below 32°F (0°C), the display will flash both
the HEAT PUMP icon and 32°F (0°C). During Heat-
Pump Lockout, the unit will not produce heat. When
temperatures below 32°F (0°C) are expected, it is
recommended to use HEAT PUMP+FURNACE Mode
or FURNACE Mode.
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Heat Pump Defrost:
In HEAT PUMP Mode, if the system detects frost build
up on the outdoor coil, the display will flash the Heat
Pump icon and cease to operate until fully defrosted.
If you are in HEAT PUMP + FURNACE Mode, the
unit will use the furnace until the heat pump is fully
defrosted.
