Old Thermostat Removal; Remove Old Thermostat - Honeywell RTH4300B1000 Installation Manual

Remove your old thermostat About your new thermostat
1. Turn off power at heating/cooling system (or fuse/circuit-breaker panel).
2. Remove cover and thermostat, but leave wallplate with wires attached.
Leave wallplate in place
Old thermostat
Cover
RTH4300B Programmable Thermostat
Is there a sealed tube containing mercury?
If so, see inside front cover of this manual
for proper disposal instructions.