Aprilaire 8551 - Manual (Page 3)

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IMPORTANT: READ ALL INSTRUCTIONS THOROUGHLY
Programming your Aprilaire ® Thermostat is done in three easy steps: setting the clock, setting the event
times, and setting your desired temperatures.
Setting Or Changing The Clock
Step 1: If you are currently in Daylight Saving Time
(first Sunday in April thru fourth Sunday in October),
press the DST button and “ “ will appear in the
lower right-hand corner of the display.
Step 2: Press the CLOCK button and “Mo”
(or another day of the week) will flash. Use the
DECREASE or INCREASE button to
change the flashing symbol to the current day
of week.
110-904 7/11/01 4:29 PM Page 3