3
HEAT PUMP TERMINAL OUTPUTS
Refer to equipment manufacturers’ instruc-
tions for specific system wiring information.
You can configure the thermostat for use
with the following heat pump system types:
HEAT PUMP TYPE 1. Single-stage
compressor system; gas or electric backup.
HEAT PUMP TYPE 2. Multi-stage or two-
compressor system; gas or electric backup.
HEAT PUMP TYPE 3. System requiring
separate signals for heat (W1, W2, W3) and
cool (Y1); gas or electric backup.
This thermostat is designed to operate a
single-transformer system. If you have a two-
transformer system, cut and tape off one
transformer. If transformer safety circuits
are in only one of the systems, remove the
transformer of the system with NO safety
circuits. If required, replace remaining
transformer with a 75VA Class II transformer.
After disconnecting one transformer, the two
commons must be jumpered together.
Use the terminal output information below to
help you wire the thermostat properly for
your heat pump system type. After wiring,
see CONFIGURATION section for proper
thermostat configuration.
THERMOSTAT TERMINALS (Upper)
L
PH
D
SA
SB
SC
O T
Malfunction Light
X-10 Module Input Not Used
Remote Sense A
Remote Sense B
Remote Sense C
Outdoor Sensor
THERMOSTAT TERMINALS (Lower)
SYSTEM
E
C
R
W3/A1
W2
E2/P
W1
Y2
Y1
B
O
G
Single-stage compressor system; gas or electric backup
Heat Pump 1*
Emergency
mode first
stage
24 Volt
(Common)
24 Volt
(Hot)
Emergency mode
3rd stage
Heat mode 3rd
stage.
Emergency mode
2nd stage.
E2 - Emergency
mode constant
output.
P - All other modes
constant output.
Heat mode
2nd stage
No Output
Heat and cool
modes 1st
stage
(compressor)
Energized in
Heat, Off,
Emergency
Mode
Energized in
Cool Mode
Blower/Fan Energized
on call for Heat and
Cool
Multi-stage or two compressor system; gas or electric backup
Heat Pump 2*
Emergency
mode first
stage
24 Volt
(Common)
24 Volt
(Hot)
Emergency mode
3rd stage
Emergency mode
2nd stage.
E2 - Emergency
mode constant
output.
P - All other modes
constant output.
Heat mode
3rd stage
Heat and cool
modes 2nd
stage
(compressor 2)
Heat and cool
modes 1st
stage
(compressor 1)
Energized in
Heat, Off,
Emergency
Mode
Energized in
Cool Mode
Blower/Fan Energized
on call for Heat and
Cool
System requiring separate signals for heat (W1, W2) and cool (Y1); gas or electric backup
Heat Pump 3**
Emergency
mode first
stage
24 Volt
(Common)
24 Volt
(Hot)
Heat mode 3rd
stage.
Emergency mode
3rd stage
Heat mode 2nd
stage.
Emergency mode
2nd stage
E2 - Emergency
mode constant
output.
P - All other modes
constant output.
Heat mode
1st stage
No Output
Cool mode 1st
stage
Energized in
Heat, Off,
Emergency
Mode
Energized in
Cool Mode
Blower/Fan Energized
on call for Heat and
Cool
* If system does not provide connection to E, jumper W1 to E to provide Aux heating in emergency mode.
** If system does not provide connection to E, jumper W2 to E to provide Aux heating in emergency mode.
