Select The Fan Setting - Honeywell RTH6400 Operating Manual

Select the fan setting

Fan
Set Clock/Day/
Auto
Schedule
Fan
Set Clock/Day/
Schedule
System
Heat
M28405
System
On Heat
M28406
RTH6400 Programmable Thermostat
Press the FAN button to select Auto or On.
In "Auto" mode (the most commonly used
setting), the fan runs only when the heating
or cooling system is on. If set to "On," the
fan runs continuously.
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