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Smart Round Thermostat
Professional Install Guide
System Types
Compatible with 24-volt systems such as forced air, hydronic, heat pump (including dual
fuel), oil, gas and electric.
Does not work with electric baseboard heat (120/240V).
Mercury Notice:
If this product is replacing a control that contains mercury in a sealed tube, do not place
the old control in the trash. Contact the Thermostat Recycling Corporation at 1-800-238-
8192 or thermostat-recycle.org for information on how and where to properly and safely
dispose an old thermostat.
Disconnect power before installation.
Can cause electrical shock or equipment damage.
Must be installed by a trained, experienced technician
Read these instructions carefully. Failure to follow these instructions can
damage the product or cause a hazardous condition.
Installation
1
Set Jumper Switches
R Jumper Switch:
For single
transformer
systems, move
switch up.
Universal Jumper Switch for humidifier, dehumidifier, or
ventilation:
For single wire
products, set
the switch to 1
Wire.
2
Wiring: Terminal Designations
L
Heat pump system monitor
C
Common wire from secondary
side of cooling transformer, if 2
transformers
W2
2nd stage heat relay (heat pump
(AUX)
auxiliary, emergency heat)
W
1st stage heat relay (changeover
(O/B)
valve for heat pumps)
U1
Universal terminal for indoor
air quality products (humidifier,
dehumidifier, ventilator)
U2
Universal terminal for indoor
air quality products (humidifier,
dehumidifier, ventilator)
For dual
transformer
systems, move
switch down.
For two wire
products,
set the switch
to 2 Wire.
K
Optional wire saver module
G
Fan relay
Y2
2nd stage compressor
contactor
Y
1st stage compressor
contactor
R
Heating power. Connect to
secondary side of heating
system transformer
Rc
Cooling power. Connect to
secondary side of cooling
system transformer
3
Connect wires and mount
wallplate
Connect wires and mount the
wall plate using screws and
anchors provided.
Note: The illustration to the right
shows the most common wiring
4
Firmly snap the thermostat
into place
The thermostat will glow and
display the screen for up to
three minutes while it starts
up.
AAA