Honeywell AQ25A Series Technical Reference Booklet page 198

Display Format
Use this parameter to choose the temperature display mode. When
the automatic mode is selected, the thermostat displays the
temperature format set on the hydronic zoning controller. If °F or °C is
selected, the thermostat displays the temperature in the selected
format respectively.
Temperature Setback
When the Unoccupied mode is activated by the hydronic zoning
controller (certain controller models only), the temperature setpoint is
lowered (set back). Use this parameter to specify the amount of
temperature setback.
Backlight
Use this parameter to choose between temporary and permanent
backlight. When temporary backlight is selected, the screen is lit for
12 seconds every time any button is pressed.
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