Replace Sensor Batteries - Honeywell Home T9 User Manual

Battery Replacement (indoor sensor)
The T9 thermostat does not use any batteries. It is powered by 24 volts from the HVAC transformer using the C (common) wire.
The wireless indoor sensors use AAA Alkaline batteries.
Batteries:
Replace batteries in your indoor sensor when a warning appears on the thermostat screen, about 60 days before batteries are
depleted.
When the sensor status light begins flashing red, battery power is critically low and will be depleted within 2–3 weeks. During
normal operation, the status light remains off.
To replace the batteries:
1. Remove cover from sensor.
2. Install 2 fresh AAA alkaline batteries. If the status light flashes green, batteries are good; if it flashes red, you must use fresh
batteries.
3. Snap cover back on sensor. The sensor will restore communication with the thermostat a few seconds after new batteries are
installed.
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