Honeywell T8400C User Manual

T8400C, T8401C AND T8424C,D ELECTRONIC THERMOSTATS
68-0180-3 6
Fig. 9. T8424 wiring connections.
The T8400C Thermostats steal power through the heating
and cooling system controls and are adaptable to most 4-wire,
18 to 30 Vac heating-cooling systems.
The T8401C and T8424C,D Thermostats are powered directly
from the system transformer and are adaptable to most
5-wire, 18 to 30 Vac heating-cooling systems. Refer to Fig. 10
through 14 for typical wiring hookups.
Fig. 10. T8400C/T8401C heat-cool wiring diagram
in single transformer system with
gas heat/electric cooling.
Fig. 11. T8400C/T8401C heat-cool wiring diagram
in oil heating/electric cooling system. Oil
primary has its own transformer.
Fig. 12. T8424C,D two-stage heat and two-stage cool
system with manual changeover wiring diagram.
TERMINAL
SCREW
M20212
G
R
C
Y
W1
B
O
FOR STRAIGHT
INSERTION STRIP
5/16 IN. (8 MM)
FOR WRAPAROUND
STRIP 7/16 IN. (11 MM)
Y2
W2
L1
(HOT)
L2
1
2
1
2
W
Y
G
R
C
COOLING
CONTACTOR
FAN
RELAY
HEATING
PRIMARY
CONTROL
24V
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
IN T8401C INSTALLATIONS, CONNECT C TERMINAL.
M11021B
T8400C, T8401C
L1
(HOT)
L1
(HOT)
L2
L2
1
1
2
1
W
Y
G
R
C
2
COOLING
CONTACTOR
FAN
RELAY
OIL PRIMARY
CONTROL
T
T
24V
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
IN T8401C INSTALLATIONS, CONNECT C TERMINAL.
M11022B
T8400C, T8401C
L1
(HOT)
L2
1
1
W2
Y
G
R
C
1ST STAGE
COOLING
2ND STAGE
COOLING
FAN
RELAY
STAGE-TWO
HEATING
Y2
24V
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
M20213
T8424
W1
STAGE-ONE
HEATING

Honeywell T8400C Specifications

General

Display	Digital
System Switching	Heat-Off-Cool
Fan Control	Auto-On
Voltage	20 to 30 Vac
Switch Type	SPDT
Control Type	Electronic
Operating Temperature Range	32°F to 122°F (0°C to 50°C)
Mounting	Wall Mount