Wiring Requirements
The following table shows the maximum wire lengths allowed:
Thermostat to HVAC Equipment
18 AWG
20 AWG
22 AWG
128 ft/380 m
80 ft/240 m
50 ft/150 m
Terminal Description and Electrical Ratings
Terminal Description
Voltage Current (Max)
N/C Unused
N/A
N/A
Y
1st stage compressor
24V AC
2A
W (O/B)
1st stage heating
24V AC
2A
or reversing valve
changeover
G
Fan
24V AC
2A
C
Common
24V AC
2A
Y2
2nd stage compressor
24V AC
2A
W2 (AUX) 2nd stage heating or
24V AC
2A
1st stage auxiliary heat
* Factory jumper installed between RC and RH. Remove jumper
for 2-transformer applications. See wiring diagrams for additional
information.
6
Summary of Contents for Smart Si
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