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T8400C1099, T8401C1031 ELECTRONIC THERMOSTATS
69-1484-2 4
Fig. 9. Typical hookup of T8401C1031 in heat-cool
system.
Fig. 10. Typical hookup of T8401C1031 in single-
stage heat pump system.
Mounting Thermostat to Wallplate
1. Engage the tabs at the top of the thermostat and
wallplate.
2. Swing down the thermostat and press the lower
edge of the thermostat onto the wallplate to latch.
See Fig. 11.
Fig. 11. Mounting thermostat wallplate.
OPERATION
Setting FAN and SYSTEM Switches
Fan and system settings are controlled manually by
using the switches located at the bottom of the
thermostat case. See Fig. 12.
FAN Switch
Fan switch settings are:
On: The fan runs continuously. Use for improved air
circulation and air quality.
Auto: Normal 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 minutes after the
heating equipment turns on (on most systems).
When using an electric heat thermostat, the fan
starts and stops with the heating equipment.
Slide the FAN switch in the bottom left corner of the
thermostat to select the desired fan setting.
L
1
(
HOT)
L
2
1
FAN
RELAY
COOL
RELAY
HEAT
RELAY
24V
M2088
1
TRANSFORMER
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
Y
G
C
W
R
B
O
L
1
(
HOT)
L
2
1
COOL
CHANGEOVER
FAN
RELAY
COMPRESSOR
24V
M2088
2
HEAT
CHANGEOVER
TRANSFORMER
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
CAN BE USED FOR CHANGEOVER VALVE ON
SINGLE-STAGE HEAT PUMP SYSTEMS.
FIELD INSTALLED JUMPER.
2
3
2
2
Y
G
C
W
R
B
O
3
M14677
SYSTEM
Cool Off Heat
Auto On
FAN
DASHED LINES INDICATE TABS
ON BACK OF THERMOSTAT
SYSTEM
Cool Off Heat
Auto On
FAN
ENGAGE TABS AT TOP OF THERMOSTAT
WITH SLOTS ON MOUNTING PLATE.
PRESS LOWER EDGE OF
CASE TO LATCH.
A
B