Honeywell RTH6400 Operating Manual page 17

Auto Changeover
If the cool temperature is lowered to where it gets close to the heat setting, an arrow
next to heat will show the thermostat is lowering the heat setting down to maintain a
3-degree separation.
Inside
73
1 : 05
Fan
Run Schedule
Auto
CAUTION: To avoid possible compressor damage, do not use Auto
Changeover if the outside temperature drops below 50ºF (10ºC).
Temporary
Heat
Setting
73
PM
Cool
Select
Heat/Cool
M27477
RTH6400 Programmable Thermostat
The triangle indicates the cool temperature is
increasing to maintain 3 degrees between heat
and cool settings.
Press Select Heat/Cool to set the heat or cool
temperature.
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