Source 1 S1-TBSU305-S Owner's Manual & Installation Instructions page 9

Get To Know Your Thermostat
Display Features
13
13 Fan On icon —Indicates constant, continuous fan operation.
When Fan On is not lit - indicates the fan will only operate
when necessary to heat or to cool.
14 Lo icon—Indicates the lowest recorded outdoor temperature
for the day.*
15 AuxHeat icon—Indicates 2nd stage electric strip heat is being
used when the thermostat is programmed for Heat Pump
operation. Only the Aux icon will appear during Cool to
Dehumidify to indicate Reheat operation.
16 Hi icon—Indicates the highest recorded outdoor temperature
for the day.*
* Hi and Lo Temperatures for the day, reset at midnight.
Program
2nd3rd
18:88
Am
Unoccupied123
Stage
Pm
188
Setup Step
Fan On
Outdoor
188
ONOFF
188
HI
Override
A H
UX EAT
88
Lo
14
5
16
15