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PRO TH4110D / TH4210D
7
The SYSTEM switch can be set to control
your heating or cooling system, depend-
ing on the season.
• Cool: Cooling system control.
• Off: All systems are off.
• Heat: Heating system control.
• Em Heat: Emergency & Auxiliary
Heat control. Compressor is locked
out. (Select models only.)
System switch
Set SYSTEM switch to control the
heating or cooling system.
CAUTION: EQUIPMENT DAMAGE
HAZARD. Do not operate cooling
system when outdoor temperature
is below 50°F (10°C).