3
RH
Y
24 VAC
120 VAC
Hot
Neutral
TRANSFORMER
THERMOSTAT
SYSTEM
G
W
Figure 3. Typical wiring diagram for
cool only, 3-wire, single transformer systems
Cooling
System
Fan
Relay
RC
O
B
C‡
JUMPER
WIRE
Figure 2. Typical wiring diagram for
heat only, 3-wire, single transformer systems
RH
Y
24 VAC
120 VAC
Hot
Neutral
THERMOSTAT
SYSTEM
G
W
TRANSFORMER
Heating
System
Fan
Relay
RC
JUMPER
WIRE
O
C‡
B
For 2-wire Heat only,
attach to RH and W
NOTE
RH
Y
24 VAC
120 VAC
Hot
Neutral
THERMOSTAT
SYSTEM
G
W
Figure 5. Typical wiring diagram for
heat/cool, 5-wire, two-transformer systems
HEATING
TRANSFORMER
Heating
System
Fan
Relay
Cooling
System
RC
24 VAC
120 VAC
Hot
Neutral
COOLING TRANSFORMER
O
B
C‡
RH
Y
24 VAC
120 VAC
Hot
Neutral
THERMOSTAT
SYSTEM
G
W
Figure 7. Typical wiring diagram for heat pump
with reversing valve energized in HEAT
TRANSFORMER
Reversing
Valve*
RC
O
B
C‡
JUMPER
WIRE
Compressor
Contactor
JUMPER
WIRE
* Reversing valve is energized when the
system switch is in the HEAT position
Fan
Relay
‡
The 24 Volt neutral connection to terminal C on the thermostat is not required if the batteries are replaced once a
year with fresh “AA” Energizer
®
alkaline batteries.
Heating System
1. Move SYSTEM switch to
HEAT
position. If the heating system
has a standing pilot, be sure to light it.
2. Press
to adjust thermostat setting above room tempera-
ture. The heating system should begin to operate.
3. Press
to adjust thermostat setting below room tempera-
ture. The heating system should stop operating.
To prevent compressor and/or property damage, if the
outdoor temperature is below 50°F, DO NOT operate
the cooling system.
1. Move SYSTEM switch to
COOL
position.
2. Press
to adjust thermostat setting below room tempera-
ture. The blower should come on immediately on high speed,
followed by cold air circulation
3. Press
to adjust thermostat setting above room tempera-
ture. The cooling system should stop operating.
Cooling System
▲
!
CAUTION
INSTALLATION
RH
Y
24 VAC
120 VAC
Hot
Neutral
THERMOSTAT
SYSTEM
G
W
Figure 4. Typical wiring diagram for
heat/cool, 4-wire, single transformer systems
TRANSFORMER
Heating
System
Fan
Relay
Cooling
System
RC
JUMPER
WIRE
O
C‡
B
RED
jumper wire (provided with thermostat)
must
be
connected between thermostat
RH
and
RC
terminals
for proper thermostat operation with this system.
NOTE
RH
Y
24 VAC
120 VAC
Hot
Neutral
THERMOSTAT
SYSTEM
G
W
Figure 6. Typical wiring diagram for heat pump
with reversing valve energized in COOL
TRANSFORMER
Reversing
Valve*
RC
O
B
C‡
JUMPER
WIRE
Compressor
Contactor
JUMPER
WIRE
* Reversing valve is energized when the
system switch is in the COOL position
Fan
Relay
