Getting Familiar with the Aprilaire Thermostat
(refer to Figure 1)
The LCD (Liquid Crystal Display) normally shows: the room temperature, the current mode of operation, if the Day or Night temperature setting is being used, and if the system fan is set for continuous operation.
Temperature Display
Room temperature can be displayed in either degrees Fahrenheit or degrees Celsius. If the displayed temperature seems abnormally high or low (example: 70˚F is equal to 21˚C), press the DECREASE 
button and INCREASE 
button simultaneously to switch between ˚F and ˚C.
Mode Button
Three modes of operation are available for all the Heat/Cool thermostat models: Heat, Cool, and Off. Additionally, with the Models 8534 and 8538, “AUtO” mode is available. The mode of operation indicates how you want your heating and cooling equipment to operate. Press the MODE button until the desired mode of operation shows on the display.
Temperature Settings - Day/Night Button
The thermostat stores four temperature settings in its memory, two for heating and two for cooling. The
two temperatures for each mode are called the Day setting ” | “ (a sun icon appears on the display) |
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