Mounting Thermostat To Wallplate; Operation; Setting Fan And System Switches - Honeywell T8400C Installation Instruction

STR_P 5/16 _N. (e M M)
Fig. 4. Wiring connections.
T8400C
_ POWER S t_PpLy_ PROWOE D_SCONNECT MEANS AND
OVERLOAD _OTECT_ON ASREQUIRED_
M109_
Fig. 5. T8400C heat-cool wiring diagram in single
transformer system with gas heat/electric cooling.
Te400C
Z_ POWER S t_PpLy_ PROWDE D_SCONNECT MEAN_ A NO
OVERLOAD PROTECTK)N ASREQU_RED_ M10_7
Fig. 6. T8400C beat-cool wiring diagram in
og heating/electric cooling system. Oil
primary has its own transformer.
T8400C ELECTRONIC THERMOSTAT
Mounting Thermostat to Wallplate
1. Engage the tabs at the top of the thermostat and
wallplate
2. Swing down the thermostat and press the _ower
edge of the thermostat onto the wallplate to latch.
See Fig 7.
DASHED L_NES _NOICA_ TABS
A ENGAGE TA£S ATTOP
OFT_4ERMOSTAT W_TH
SLOTS O N WALLPLATE
M18416 B PRESS LOWER E DGE O F
CASE TO£AT¢_4
Fig= 7. Mounting thermostat wallplate.
OPERATION
Setting FAN and SYSTEM Switches
Fan and system settfngs are controfled manuafly by
using the switches located at the bottom of the
thermostat case See Fig 8
FAN Switch
Fan switch settings are:
On: The fan runs continuously Use for improved air
circulation and air quality
Auto: Norma_ setting for most homes In cooling, the
fan starts and stops with the cooling equipment. In
heating, the fan is controlled directly by the heating
equipment and may start a few mfnutes after the
heating equipment turns on (on most systems)
When using an electric heat thermostat, the fan
starts and stops wdh the heating equipment
Slide the switch in the bottom left corner of the
thermostat to select the desired fan setting
SYSTEM Switch
System switch settings control thermostat operation as
follows:
Cool: The thermostat controls the cooling system.
Off: Both heating and cooling are off
Heat: The thermostat controls the heating system
Slide the switch in the bottom right corner of the
thermostat to select the desired system setting
3 69-1485-1