33-00235 4
1H/1C System
(1 transformer)
Rc
Power
[1]
R
[R+Rc joined by jumper loop]
Y
Compressor contactor
C
24VAC common
W
Heat relay
G
Fan relay
Heat-only System
Rc
Power
[1]
R
[R+Rc joined by jumper loop]
C
24VAC common
W
Heat relay
1H/1C System
(2transformers)
Rc
Power (cooling transformer)
[1, 2]
R
Power (heating transformer)
[1, 2]
Y
Compressor contactor
C
24VAC common
[3]
W
Heat relay
G
Fan relay
Heat-only System
with Fan
Rc
Power
[1]
R
[R+Rc joined by jumper loop]
C
24VAC common
W
Heat relay
G
Fan relay
Wiring
Wiring Guide
— Conventional Systems
NOTES
Wire specifications: Use 18- to 22-gauge thermostat wire. Shielded cable is not required.
[1]
For power supply, provide a means of disconnection and overload protection.
[2]
Remove jumper loop for 2-transformer systems.
[3]
Common connection must come from cooling transformer.
Wiring Instructions
1. This thermostat requires a 24VAC common wire to power-up. The K terminal is available
for Wiresaver module (THP9045A1023).
2. Straighten the wire. Using a pen’s tip, hold down the terminal and gently slide the wire
into the terminal hole.
Note
: Terminal hole will only accept one wire.
Jumper Loop
Cool-only System
Rc
Power
[1]
R
[R+Rc joined by jumper loop]
Y
Compressor contactor
C
24VAC common
G
Fan relay
2H/2C System
(1 transformer)
Rc
Power
[1
]
R
[R+Rc joined by jumper loop]
Y
Compressor contactor (stage 1)
C
24VAC common
W
Heat relay (stage 1)
G
Fan relay
W2
Heat relay (stage 2)
Y2
Compressor contactor (stage 2)
2H/2C System
(2 transformers)
Rc
Power (cooling transformer)
[1, 2]
R
Power (heating transformer)
[1, 2]
Y
Compressor contactor (stage 1)
C
24VAC common
[3]
W
Heat relay (stage 1)
G
Fan relay
W2
Heat relay (stage 2)
Y2
Compressor contactor (stage 2)
See
[notes]
below
