Ecobee ecobee3 lite User manual

How to install
your ecobee3 lite

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do something good for our planet.
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Or continue reading!
Download the ecobee
app for customized
installation instructions.

Table of contents
What’s in the box
Guide 1 or Guide 2?
Guide 1: Install with a C-wire
Guide 2: Install without a C-wire
Extras
5
7
14
29
54

First things first. Here’s what
you’ll find in the box.
PEK
W2
W1
RH
Rc
G
Y1
Y2
O/B
C
ecobee thermostat ecobee backplate Power Extender Kit
(PEK)
Drywall plugs
Screws
Install guide (this booklet)
and wire labels
Trim plate

You’ll also need these tools:
OPTIONAL
Drill for mounting anchors
(3/16” drill bit)
Hammer
Small flathead
screwdriver
Pencil
Phillips
screwdriver
Wire stripper

Guide 1 or Guide 2?
Start here to find out.
The steps in this section will help
you decide which install guide you’ll
use to complete the installation.
These icons indicate useful tips and important reminders.

STEP 1
TIP:
Look for your master switch or circuit breaker box in the basement,
attic, utility closet, or behind a wall panel near the thermostat.
Power off your Heating, Ventilation and Air
Conditioning (HVAC) system by using the
master switch or circuit breaker box. This is
important for your safety.
ON OFF
ON
OFF
OR

Confirm your system is off by turning on
your heat (during winter) or your AC (during
summer). Wait a few minutes - you should
not feel air coming from your vents.
STEP 2
TIP:
If you have a boiler, check to see that the main flame is extinguished.

STEP 3
Remove your old thermostat cover from
the wall.
TIP:
Many thermostats simply pop off or unclip from the base,
while others may have screws that you will need to remove.
OR

Great, please
continue to
the next page
Sadly, you might
not be compatible
You can double check here:
ecobee.com/compatibility
Does your old thermostat’s backplate have
any of these indicators?
CHECKPOINT: COMPATIBILITY
L1 L2
WARNING
HIGH VOLTAGE
110 VAC
OR
120 VAC
OR
240 VAC
YES NO

STEP 4
Take a picture of the wires connected to the
terminals of your old thermostat. You may
need to reference this photo later on.
WARNING:
ecobee3 lite is designed for 24VAC with a 2A maximum current.
Do not connect it to line (high) voltage or millivolt systems.

CHECKPOINT: C WIRE
Do you have a C wire connected to your
old thermostat?
YES NO
RCRHRCRH
Continue to
Guide 1
Continue to
Guide 2
YES NO
OR

GUIDE 1
Install your ecobee
with a C wire
If you have a C wire, it will power your
ecobee. You won’t need the Power
Extender Kit included in the box.

CHECKPOINT: DON’T SKIP AHEAD
Have you completed steps 1 - 4 in the ‘Start
Your Install’ section?
Continue to
the next page
Return to step 1
in ‘Start Your Install’
YES NO

STEP 5
Carefully disconnect and label the wires from
your old thermostat one at a time, using the
labels provided.
TIP:
If you have a jumper between Rc, Rh or R, leave it alone. Only label
the wires that run from your wall into a terminal block.
W/W1
Y/Y1
Rc
RCRH

Unscrew the mounting plate of your old
thermostat to remove it from the wall.
STEP 6
WARNING:
Be careful, as some thermostats may contain mercury. Recycle your
old thermostat safely with your local hazardous waste facility.
R
C
RCRH
W/W1
Y/Y1

STEP 7
Decide if you want to use the trim plate with
your ecobee. The trim plate is useful if you
want to hide marks or holes left on the wall
by your old thermostat.
PEK
W2
W1
RH
Rc
G
Y1
Y2
O/B
C
PEK
W2
W1
RH
Rc
G
Y1
Y2
O/B
COR

STEP 8: OPTIONAL
If using the trim plate, align the mounting
holes on the trim plate and backplate and
press them into place together.

STEP 9
Pull the wires through the hole in the
middle of the backplate and then attach
the backplate to the wall using the drywall
anchors and screws provided.
TIP:
Use a 3/16” drill bit to drill a hole for the drywall plugs.
Rc
G
Y/Y1
W/W1
C