Honeywell T8112D User Manual

Page of 8
T8112D PROGRAMMABLE THERMOSTAT
68-0206
4
Fig. 3. Proper wiring technique.
M1712A
JUMPER (FACTORY-
INSTALLED) REMOVE 
IF 5-WIRE SYSTEM
INSERT
STRAIGHT 
UNDER 
SCREW HEAD
5/16 in. 
(8 mm)
STRIP 
END OF WIRE 
VISIBLE HERE
R
Rc
W
Y
G
Fig. 4. Holding thermostat while installing.
M3002A
Fig. 5. 2-wire heat-only application (jumper intact).
R
Rc
W      Y      G
B               D
A               C
2-WIRE HEAT-ONLY (JUMPER INTACT)
M1709B
L1
(HOT)
L2
POWER SUPPLY.  PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
1
1
HEATING
RELAY OR
VALVE COIL
JUMPER
Fig. 6. 3-wire cool-only application (jumper intact).
R
Rc
W      Y      G
B               D
A               C
3-WIRE COOL-ONLY (JUMPER INTACT)
L1
(HOT)
L2
POWER SUPPLY.  PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
1
JUMPER
M848A
COOLING
CONTACTOR
COIL
FAN
RELAY
Fig. 7. 4-wire heat/cool application (jumper intact).
R
Rc
W      Y      G
B               D
A               C
4-WIRE HEAT/COOL (JUMPER INTACT)
L1
(HOT)
L2
POWER SUPPLY.  PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
1
JUMPER
HEATING
RELAY OR
VALVE COIL
M1710B
COOLING
CONTACTOR
COIL
FAN
RELAY