Honeywell RTH8500D User Manual

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24

This thermostat is designed to automatically keep current time and 

day in memory for up to ten years, under normal use, once the 

calendar is set. When the thermostat is first powered, the display is 

ready to set the calendar.

1. Use the arrow keys to set the year, month and day.

2. Press the Done key.

The calendar can be set any time. See Step 11, Configure 

Installer Setup, for instructions.

DONE

MON

TUE

WED

THU

FRI

M22226

W

USE  
ARROWS 
TO SET  
YEAR

SET 
CURRENT 
DATE

SET 
MONTH