Wiring Guide - Heat Pump Systems (24Vac) - Emerson 810-1600 Installation And Operation Manual

R 24VAC Power Supply
Rc 24VAC Power Supply for Y1, Y2
C 24VAC Power Supply Common
Y1 Cool Stage 1, relay output
Y2 Cool Stage 2, relay output
W1 Heat Stage 1, relay output
W2 Heat Stage 2, relay output
G Fan Control, relay output
Table 2-6 - Dual Transformer System
For systems with only one stage, second stage terminals (Y2,W2) can be left 
floating (open).

2.4.6. Wiring Guide - Heat Pump Systems (24VAC)

Shorting
Jumper
For systems with only one stage, second stage terminal (Y2) can be left floating
(open).
*
NOTE: Stage 1 and Stage 2 for Heat Pumps are Compressor Stages (Heat/Cool) and not
only Cool Stages.
8 • Emerson Programmable Touchscreen Thermostat I&O Manual
2H / 2C System with 2 Transformers
R 24VAC Power Supply
Rc 24VAC Power Supply for Y1, Y2
C 24VAC Power Supply Common
Y1 *Cool Stage 1, relay output
Y2 *Cool Stage 2, relay output
O/B Reversing Valve, relay output
G Fan Control, relay output
Table 2-7 - Heat Pump Systems
2H / 2C System
026-1739 Rev 0