Honeywell RTH8500WF User manual

Quick Start Guide
Wi-Fi Touchscreen
Programmable
Thermostat
RTH8500WF Wi-Fi Series

2
Install your thermostat.
Connect your home Wi-Fi network.
Register online for remote access.
Before you begin
1
2
3
Welcome
Getting set up and ready is simple.
View the installation video at
wifithermostat.com/support
Gather
• Smallscrewdriver
• ThermostatIDcard
• YourhomeWi-Fi
network password

3
This thermostat works with common 24 volt
systems such as forced air, hydronic, heat
pump, oil, gas, and electric.
It will not work with millivolt systems, such as
a gas fireplace, or with 120/240 volt systems
such as baseboard electric heat.
1.1 Switch OFF power to your
heating/cooling system
1.1a Important! To protect your
equipment, switch OFF the
power to your heating/cooling
system at the breaker box or
the system switch.
1.1b Confirm power is OFF.
Try to turn on heating/
cooling equipment by
changing temperature
on your old thermostat.
  YourpowerisOFFifyour
system does not turn ON.
Install your thermostat
1
or
M31535
Circuit
breaker
box
Heating/cooling
system power
switch

4
If you have an older thermostat with a
sealed mercury tube, see warning page
for proper disposal instructions.
1.2 Remove old thermostat
faceplate and leave wires
connected
1.2a Take a picture of the
wire connections for
later reference.
1.2b If no wire is connected
to a terminal labeled C
or no C terminal exists
on the old thermostat,
view the Alternate Wiring videos at
wifithermostat.com/videos
Important! C wire is required and is the
primary power source for your thermostat.
Without a C wire, your thermostat will not
power up.
C
C
MCR33823

5
C
C
MCR31537
Blank
sticky
tag
Terminal
designation
1.3 Label wires
Do not label by wire color.
Use the supplied sticky tags to label
each wire as you disconnect it. Label
wires according to old thermostat
terminal designations, not by wire
color.
Note: If no tag matches a terminal
designation, write the appropriate
letter on a blank sticky tag.
1.4 Remove wallplate
Remove the old wallplate from
the wall after all wires are
labeled and disconnected.
Sticky
tag

6
M31538
Finger holds
Wallplate (back view)
Thermostat
1.5 Separate Wi-Fi thermostat
and its wallplate
On your new thermostat, grasp the
finger holds on the top and bottom of
the wallplate with one hand and the
thermostat (front) with the other
hand. Pull pieces apart.

7
Wallplate
1.6 Mount wallplate for Wi-Fi
thermostat
Mount your new wallplate using screws
and anchors included with the
thermostat.
If necessary:
 • Drill3/16-inholesfordrywall
 • Drill7/32-inholesforplaster
Note: Youmaybeabletouseyour
existing wall anchors. Hold the wallplate
up to the existing anchors to check
for alignment.
M31543
Y2
W2
K
RC
R
W
Y
G
C
RC
R
O/B
Y
G
C
HEAT PUMP
CONVENTIONAL
L
E/AUX
K
R
Y
C
W
G
MCR31539

8
Y2
W2
K
RC
R
W
Y
G
C
RC
R
O/B
Y
G
C
R
W
G
C
Y
HEAT PUMP
CONVENTIONAL
L
E/AUX
K
MCR31541A
1.7 Connect wires
1.7a StartingwiththeCWire,matchthe
sticky tag on the wire to the terminal
labels.
Important! C wire is required and is the
primary power source. Without a C wire,
your thermostat will not power up.
View the Alternate Wiring videos at
wifithermostat.com/videos
 1.7b Loosenscrew,insertwireoninside
edge of terminal, then tighten screw.
 1.7c Verifywireisfirmlysecuredbygently
pulling on wire.
 1.7d Repeatsteps1.7a–1.7cforallotherwires.
 1.7e Pushanyexcesswirebackintothewall
opening after all wires are installed.
Note:The wiring for your
application might be different
than the wiring from above.
Labels don’t match or have heat pump system?
See User Guide.
Remove metal jumper only if you
have both Rand RC wires
Insert wires here

9
1.8 Install battery
Insert the coin cell battery
(included), observing
the correct polarity.
Note: A correctly inserted battery will
extend about halfway out of the battery
slot on the thermostat, allowing for
easier removal.
This battery maintains time and date
during power outages. It does not
power the thermostat (C wire
required).
1.9 Attach thermostat
to wallplate
Align the thermostat onto
wallplate and snap into place.
M31542
Thermostat interior
Thermostat
Wallplate
M31543
Y2
W2
K
RC
R
W
Y
G
C
RC
R
O/B
Y
G
C
HEAT PUMP
CONVENTIONAL
L
AUX
/E
K

10
Circuit
breaker
box
Heating/cooling
system power
switch
1.10 Switch heating/cooling system ON
Important!
1.10a Verify that the C
wire is connected at the
thermostat and at the
heating/cooling system.
1.10b Make sure the heating/cooling
system door is firmly secured.
1.10c Switch power back ON for
your heating/cooling system
at the breaker box or its
power switch.
or
M31544