Honeywell RTH7500D Owner's Manual page 51

The Filter Timer notifies you when to change your furnace
filter.
Reset Filter Timer
1. "Change Filter" appears on the display when the
filter timer expires.
2. Press the Reset button to restart the filter timer.
See Step 11 to turn the Filter Timer Change
Reminder feature on or off.
Use Your Filter Timer
Tue
System Fan
Heat
Schedule
Reset
51
PM
Clock & More
M22338
69-1730