
2 • Emerson Programmable Touchscreen Thermostat I&O Manual
026-1739 Rev 0
1.2. Terminal Identification and Electrical Ratings
C
24AVAC Power Supply Common
18-30VAC 50/60Hz
2.0A
R
24AVAC Power Supply
18-30VAC 50/60Hz
2.0A
W1
Heat Stage 1, relay output
18-30VAC 50/60Hz
1.0A
W2
Heat Stage 2, relay output
18-30VAC 50/60Hz
1.0A
AUX
Dehumidification, relay output
18-30VAC 50/60Hz
1.0A
O/B
Reversing Valve, relay output
18-30VAC 50/60Hz
1.0A
Rc
24VAC Power Supply for Y1, Y2
18-30VAC 50/60Hz
2.0A
Y1
Cool Stage 1, relay output
18-30VAC 50/60Hz
1.0A
Y2
Cool Stage 2, relay output
18-30VAC 50/60Hz
1.0A
ECO
Economizer, relay output
18-30VAC 50/60Hz
1.0A
G
Fan Control, relay output
18-30VAC 50/60Hz
1.0A
GND
Reference for DC Signals
B+
RS-485 B+ Signal
A-
RS-485 A- Signal
IN1
Remote 10K thermistor (Indoor)
0-3.3VDC (10K NTC)
IN2
Remote 10K thermistor (Outdoor)
0-3.3VDC (10K NTC)
IN3
Remote 10K thermistor (Supply)
0-3.3VDC (10K NTC)
IN4
Remote Humidity sensor (0-5V)
0-5VDC
IN5
Fan proof input
0VDC or floating
GND
Reference for DC Signals
Signal
Name
Description
Voltage
Maximum Current
Rating
Table 1-2
- Terminal Identification and Electrical Ratings