About Advanced Features & Operation
Page 16
2 STAGE OPERATION - The 2nd Stage of heat or cool is
       turned on when (1) the 1st Stage has been on for a
       minimum of two minutes, and (2) the temperature spread
       from the setpoint is equal to or greater than: the setpoint
       plus the deadband, plus 2 degrees.
Heat
Setpoint
Cool
Setpoint
Dead
Band
Dead
Band
2 degrees
2 degrees
1st Stage
turn on
2nd Stage
turn on
1st Stage
turn on
2nd Stage
turn on
Heating
Cooling
MINIMUM HEAT/COOL SETPOINT DIFFERENCE - The Heat
       and Cool setpoints will not be allowed to come any closer
       to each other than the value set in Advanced Setup step
 # 7, on page 13.  This minimum difference is enforced
       during Auto changeover  operation.
 
 
and Program On