T8775A,C THE DIGITAL ROUND™ NON-PROGRAMMABLE THERMOSTATS

69-1677EF—1 2

Wiring

IMPORTANT

Use 18-gauge wire to wire the T8775A,C

Thermostats.

All wiring must comply with local electrical codes

and ordinances. Disconnect the power supply to

prevent electrical shock or equipment damage.

Refer to Fig. 2 through 6 for typical wiring hookups.

Fig. 2. Typical hookup of T8775A in a heat-only system.

Fig. 3. Typical hookup of T8775C in heat-only system

with fan.

Fig. 4. Typical hookup of T8775C in heat-cool system

with single transformer.

Fig. 5. Typical hookup of T8775C in heat-cool system

with two transformers.

Fig. 6. Typical hookup of T8775C in single-stage heat

pump system.

POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
W
R
HEATING
RELAY OR
VALVE COIL
M19513
1
1
M19514
HEATING
RELAY OR
VALVE COIL
FAN
RELAY
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2 FACTORY INSTALLED JUMPER.
1
2
W
R
Rc B
O
Y
G
1HEATING
RELAY OR
VALVE COIL
COMPRESSOR
CONTACTOR FAN
RELAY
M19515
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2 FACTORY INSTALLED JUMPER.
2
W
R
Rc B
O
Y
G
1
2
1
HEATING
RELAY OR
VALVE COIL
COMPRESSOR
CONTACTOR
FAN
RELAY
M19517
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
REMOVE FACTORY INSTALLED JUMPER BETWEEN R AND RC.
2
W
R
Rc B
Y
G
1
4
COMPRESSOR
CONTACTOR
HEAT
CHANGEOVER
VALVE
COOL
CHANGEOVER
VALVE
FAN
RELAY
M19516
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2 FACTORY INSTALLED JUMPER.
3 USE A JUMPER WIRE (NOT SUPPLIED) TO CONNECT W TO Y.
4 USE EITHER O OR B FOR HEAT PUMP CHANGEOVER.
3
2
W
R
Rc B
O
Y
G