Installation - Emerson Sensi ST75 Installation Manual

Installation

1. Install Sensi thermostat, referring to these terminal
definitions, cross references and wiring diagrams as needed:
OLD
THERMOSTAT
RH
RC, R
C, X, B**
Y, Y1
Y2
W, W1, W/E,
Aux/E, E
W2***
G
O,B,** O/B
L
* Two transformer systems (separate RC and RH wires), clip jumper located
on backplate to the right of the terminals.
** Label "B" as "C" only if the old thermostat also had a wire in "O" . If there is no wire
on "O"-label the wire "B" .
*** On Heat Pump system with separate W2 and E wires, label both wires W/E
(2 wires in one terminal).
6
SENSI
THERMOSTAT
RH*
RC*
C
Y
Y2/*
W/E
W2
G
O/B
L
CONVENTIONAL
SYSTEM
Power for heating, 24V
Power for cooling, 24V
Common wire, 24V
1st stage cool
2nd stage cool
1st indoor
stage heat
2nd indoor
stage heat
Indoor blower (fan)
Changeover (reversing valve) connection
for heat pump or zone panel systems
no function
HEAT PUMP
SYSTEM
1st outdoor
stage heat
2nd outdoor stage
heat and cool
1st stage axillary/
emergency heat
2nd stage axillary/
emergency heat
"L" terminal
connection