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Single
Stage 1
(SS1)
Multi-
Stage 2
(MS2)
O
Energized Constantly
in Cool Mode
B
Energized Constantly
in Heat, Off,
Emergency
Mode
No
Output
Cool
Mode
2nd
Stage
Cool Mode
1st Stage
Blower/
Circulator
Fan Energized
on Call for
Cool (and
Heat if
configured
for Electric
Heat)
No Output
Heat Mode
2nd Stage
Heat
Mode
1st Stage
Optional*
24 Volt
(Com-
mon)
24 Volt
(Hot)
Cool
System
Y G W/E C L RC
CLASS II
TRANSFORMER
HOT
24VAC
NEUTRAL
120VAC
24 Volt
(Hot)
Heat
RH Y2 W2
Jumper
Fault
Indicator
or
System
Malfunction
Switch
Comfort Alert II Module
or Similar System
Malfunction Module
O/B
Heat Pump 2
(HP2)
Heat Pump 1
(HP1)
O
Energized in
Cool Mode
B
Energized in
Heat, Off,
Emergency
Mode
2nd
Stage
(Com-
pressor)
No
Output
Heat and
Cool Mode
1st Stage
(Compressor)
Blower/
Circulator
Fan Energized
on Call for
Heat or Cool.
Set Elect/Gas
Option for
Emergency
Mode
Heat Mode
2nd Stage.
Emergency
Mode 2nd
Stage
Heat Mode
3rd Stage.
Emergency
Mode 2nd
Stage
Emergency
Mode
1st Stage
Optional*
24 Volt
(Com-
mon)
Fault Indicator
or System
Malfunction
Switch
24 Volt
(Hot)
Cool
System
Y W/E C L RC
CLASS II
TRANSFORMER
HOT
24VAC
NEUTRAL
120VAC
24 Volt
(Hot)
Heat
RH
Jumper
Y2 W2 G
Jumper
Comfort Alert II Module
or Similar System
Malfunction Module
O/B
TYPICAL WIRING 1F83-0471
Heat Pump Systems
NOTE: If your system
does not provide an
E connection, jumper
W2 to W/E to use the
Auxiliary Heat in the
Emergency Mode.
* Common connection
required for fault or
malfunction indication.
Single Stage or Multi-Stage System (No Heat Pump) with Single Transformer
* Common connection
required for fault or
malfunction indication.
Single Stage or Multi-Stage System (No Heat Pump) with Two Transformers
Single
Stage 1
(SS1)
Multi-
Stage 2
(MS2)
No
Output
Cool
Mode
2nd
Stage
Cool Mode
1st Stage
Blower/
Circulator
Fan Energized
on Call for
Cool (and
Heat if
configured
for Electric
Heat)
No Output
Heat Mode
2nd Stage
Heat
Mode
1st Stage
Optional
24 Volt
(Com-
mon)
Fault
Indicator
(NOT
USED)
24 Volt
(Hot)
Cool
System
Y G W/E C L RC
CLASS II
TRANSFORMER
HOT
24VAC
NEUTRAL
120VAC
24 Volt
(Hot)
Heat
RH
120VAC
Remove Jumper Wire
between RH & RC
HOT
24VAC
NEUTRAL
CLASS II
TRANSFORMER
HEATING
COOLING
Y2 W2
Jumper
O/B
O
Energized Constantly
in Cool Mode
B
Energized Constantly
in Heat, Off,
Emergency
Mode
NOTE: If continuous backlight or hardwired power input are desired but do
not function in both HEAT and COOL modes, cut the heating transformer 24V
wires and tape off. Connect the neutral circuit disconnected from the heating
transformer to the neutral circuit of the cooling transformer. Disconnect the wire
to the RH terminal and install a jumper between RH and RC. Depending on
the system requirements, replace the cooling transformer with a 75VA class II
transformer if needed.
TYPICAL WIRING DIAGRAMS
148
TECHNICAL HELP