Honeywell CHRONOTHERM IV T8665A User Manual page 22

2. Remove the thermostat by placing your thumb
between the thermostat and wallplate and
pulling the thermostat up and away as shown.
If you insert new batteries within 20 to 30 seconds of
removing the old batteries, the system retains the
current time and day. If the display is blank, the
batteries are dead or installed incorrectly. You must
reset the time and day. Refer to Setting the Clock
section for instructions.
Nonalkaline batteries do not last as long; they also
can leak, causing damage to the thermostat and the
wall surface. Honeywell recommends Energizer®
batteries.
M16424
22
As a precaution when leaving home for
longer than a month, change batteries
before leaving to prevent the system from
shutting down due to lack of power.
Always use fresh alkaline batteries.
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