Set Fan Operation Switch - Honeywell RTH4300B Installation Manual

Set fan operation switch

About your new thermostat
Move the switch to the proper setting:
F: For gas or oil heating systems, leave
the fan operation switch in this factory-set
position (for systems that control the fan in
a call for heat).
E: Change the switch to this setting for heat
pump or electric heat systems. (This setting
is for systems that allow the thermostat to
control the fan in a call for heat, if a fan wire
is connected to the G terminal.)
RTH4300B Programmable Thermostat