4
MOUNTING AND WIRING
CONTINUED FROM SECOND PAGE
B
O
Y
G
Fan
Relay
NOTE
For 2-wire Heat only,
attach to RH and W
Figure 2. Typical wiring diagram for
heat only, 3-wire, single transformer systems
B
O
Y
Cooling
System
Figure 3. Typical wiring diagram for
cool only, 3-wire, single transformer systems
NOTE
RED jumper wire (provided with thermostat) must be
connected between thermostat RH and RC terminals
for proper thermostat operation with this system.
B
O
Y
Cooling
System
Figure 4. Typical wiring diagram for
heat/cool, 4-wire, single transformer systems
5
CHECK THERMOSTAT OPERATION
To prevent static discharge problems, touch side of thermo-
stat to release static build-up before touching any keys.
If at any time during testing your system does not operate properly,
contact a qualifi ed serviceperson.
Fan Operation
If your system does not have a G terminal connection, skip to
Heating System.
1. Turn on power to the system.
2. Move FAN switch to ON position. The blower should begin to
operate.
3. Move FAN switch to AUTO position. The blower should stop
immediately.
Cooling System
CAUTION
!
To prevent compressor and/or property damage, if the
outdoor temperature is below 50°F, DO NOT operate the
cooling system.
JUMPER
WIRE
THERMOSTAT
W
RC
RH
SYSTEM
Heating
System
Hot
24 VAC
120 VAC
Neutral
TRANSFORMER
JUMPER
WIRE
THERMOSTAT
G
W
RC
RH
SYSTEM
Fan
Relay
Hot
24 VAC
120 VAC
Neutral
TRANSFORMER
JUMPER
WIRE
THERMOSTAT
G
W
RC
RH
SYSTEM
Fan
Heating
Relay
System
Hot
24 VAC
120 VAC
Neutral
TRANSFORMER
NOTE
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Y
B
O
G
Cooling
Fan
System
Relay
Figure 5. Typical wiring diagram for
heat/cool, 5-wire, two-transformer systems
JUMPER
Y
B
O
Reversing
Compressor
Valve*
Contactor
* Reversing valve is energized when the
system switch is in the COOL position
Figure 6. Typical wiring diagram for heat pump
with reversing valve energized in COOL
JUMPER
B
O
Y
Reversing
Compressor
Valve*
Contactor
* Reversing valve is energized when the
system switch is in the HEAT position
Figure 7. Typical wiring diagram for heat pump
with reversing valve energized in HEAT
This thermostat has a time delay between cooling cycles to allow
the head pressure in the compressor to stabilize. If the temperature
is adjusted to call for cool within 5 minutes of the last cycle the
snowfl ake icon will blink indicating the thermostat is locked out. After
3 to 5 minutes, the compressor will start and the snowfl ake icon will
stop fl ashing. This helps prevent the compressor from cycling too
quickly and is normal operation for the thermostat.
1. Move SYSTEM switch to COOL position.
2. Press
to adjust thermostat setting below room temperature.
The blower should come on immediately on high speed, followed
by cold air circulation
3. Press
to adjust temperature setting above room
temperature. The cooling system should stop operating.
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 temperature.
The heating system should begin to operate.
3. Press
to adjust temperature setting below room temperature.
The heating system should stop operating.
THERMOSTAT
W
RC
RH
SYSTEM
Hot
Heating
24 VAC
120 VAC
System
Neutral
HEATING
TRANSFORMER
Hot
24 VAC
120 VAC
Neutral
COOLING TRANSFORMER
JUMPER
WIRE
WIRE
THERMOSTAT
G
W
RC
RH
SYSTEM
Fan
Hot
Relay
24 VAC
120 VAC
Neutral
TRANSFORMER
JUMPER
WIRE
WIRE
THERMOSTAT
G
W
RC
RH
SYSTEM
Fan
Hot
Relay
24 VAC
120 VAC
Neutral
TRANSFORMER