Honeywell RTH5100B Manuel Du Propriétaire page 11

Auto Changeover
Use this feature in climates where both air conditioning and heating are used on
the same day. When the system mode is in Auto, the thermostat automatically
selects heating or cooling depending on the indoor temperature.
While in the Auto mode, if a schedule override takes place (temporarily or
permanently) the thermostat will automatically adjust the cooling and heating
settings to maintain a 3-degree separation between the cool and heat settings.
For example, if the heat temperature is raised to where it gets within 3-degrees
of the cool setting, the display will show an up arrow next to "cool" to show the
thermostat is raising the cool setting up to maintain a 3-degree separation.
Press the Select Heat/Cool button to select between the heat and cool to view/
adjust either mode.
Fan System
Auto Auto
MCR29531
NOTICE: To avoid possible
compressor damage, do not use
Auto Changeover if the outside
temperature drops below 50ºF (10ºC).
11