Remove Old Thermostat; Cooling System - Honeywell RTH7400 series Quick Start Manual

Turn OFF
1

Cooling System

2

Remove Old Thermostat

Remove old thermostat but leave wallplate with
wires attached.
Leave wallplate
in place
Old thermostat
Power to Heating/
or
Is there a sealed tube containing
mercury? If so, see back cover
for proper disposal instructions.
EM. HEAT AUX. HEAT
50 60
50 60 70 80 F
EM. HEAT
Cover
3
70 80
AUTO OFF
MCR33835A