Honeywell T8400C Installation Instructions Manual page 3

Wiring
IMPORTANT
Use an 18-gauge maximum wire for wiring the
T8400C Thermostat.
All wiring must comply with local electrical codes and
ordinances. Disconnect the power supply to prevent
electrical shock or equipment damage.
NOTE: To ensure proper mounting of thermostat, restrict
all wiring to the shaded area. See Fig. 4.
The shape of the terminals permits insertion of straight or
wraparound wiring connections; either method is accept-
able. See Fig. 5.
KEEP WIRING IN
SHADED AREA
G
Rc
R
W
Y
WIRING ENTRANCE
MOUNTING
HOLE
SCREW HOLE
Fig. 4. Restrict wiring to shaded area.
The T8400C Thermostat is powered through the heating/
cooling system controls and is adaptable to most 4-wire,
24 Vac heating-cooling systems.
Refer to Fig. 6, 7, and 8 for typical wiring hookups.
B
O
MOUNTING
SCREW HOLE
Fig. 6. Typical hookup of T8400C in heat-cool system
M16432
3
T8400C ELECTRONIC THERMOSTAT
TERMINAL
SCREW
G
Rc
R
W
Y
Fig. 5. Wiring connections.
G
Rc
2
R
W
B
Y O
HEATING
1
PRIMARY
CONTROL
L1
(HOT)
24V
L2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
1
OVERLOAD PROTECTION AS REQUIRED.
FACTORY INSTALLED JUMPER.
2
with single transformers.
FOR STRAIGHT INSERTION
STRIP 5/16 IN. (8 MM)
FOR WRAPAROUND
STRIP 7/16 IN. (11 MM)
B
O
M13274
COOLING
CONTACTOR
FAN
RELAY
M13275
69-1493–1