Honeywell RTH8500 Series User manual

User Guide
Read and save these
instructions.
For help please visit
yourhome.honeywell.com
RTH8500
Wi-Fi Series
Wi-Fi Touchscreen
Programmable
Thermostat
In the box you will find
• Thermostat
• Wallplate (attached to thermostat)
• Screws and anchors
• Coin cell battery (inside the back
of the thermostat)
• Quick Start Guide
• Thermostat ID Card
• Wire labels
• User Guide
This is a legacy product document
supported by Resideo. It is no
longer manufactured

33-00133ES—01 ii
Welcome
Congratulations on your purchase of a
Honeywell Wi-Fi touchscreen programmable
thermostat. When registered to Honeywell’s
Total Connect Comfort Solutions, you can
remotely monitor and control the heating and
cooling system in your home or business—you
can stay connected to your comfort system
wherever you go.
Honeywell’s Total Connect Comfort is the
perfect solution if you travel frequently, own
a vacation home, a business or manage an
Investment property or if you are simply looking
for peace of mind.
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.
This thermostat contains a Lithium battery which may contain Perchlorate material.
Perchlorate Material—special handling may apply.
See www.dtsc.ca.gov/hazardouswaste/perchlorate
MERCURY NOTICE: Do not place your old thermostat in the trash if it contains
mercury in a sealed tube. Contact the Thermostat Recycling Corporation at www.
thermostat-recycle.org or 1-800-238-8192 for information on how and where to
properly and safely dispose of your old thermostat.
NOTICE: To avoid possible compressor damage, do not run air conditioner if the
outside temperature drops below 50°F (10°C).
Need help?
Visit wifithermostat.com or call 1-855-733-5465 for assistance before returning the
thermostat to the store.

1 33-00133ES—01
About your new thermostat
Home screen quick reference .....................2
Preset energy-saving schedules................. 2
Installation
Installing your thermostat............................ 3
Connecting to your Wi-Fi network............. 11
Registering your thermostat online ...........12
Operation
Setting the clock........................................14
Setting the fan........................................... 15
Selecting system mode............................. 15
Adjusting program schedules....................16
Overriding schedules temporarily .............16
Overriding schedules permanently ...........16
Setting vacation hold.................................17
Setting filter reminder intervals .................17
Cleaning the screen..................................18
Unregistering thermostat...........................18
Disconnecting Wi-Fi ..................................18
Special features ........................................19
Setting functions and options....................20
Appendices
Frequently asked questions ...................... 24
Message center messages.......................25
Troubleshooting......................................... 26
Limited warranty........................................27
Table of contents
Features of your Wi-Fi thermostat
With your new thermostat, you can:
• Connect to the Internet to monitor and control your heating/cooling system
• View and change your heating/cooling system settings
• View and set temperature and schedules
• Receive alerts via email and get automatic upgrades
Your new thermostat provides:
• Smart Response Technology
• Compressor protection
• Heat/cool auto changeover

33-00133ES—01 2
Home screen quick reference
Once your Wi-Fi thermostat is installed, it will display the home screen. Portions of this
display will change depending on how you are viewing it. To change settings, simply press
the appropriate area lightly with your finger.
Unless you change the lighting function, the screen is always lit at low intensity. When you
touch the screen, the screen brightens.
Set clock
Message center
Select fan mode
Select system mode
Program schedules
Override schedule
Wi-Fi status
Schedule is on (does not
display when off)
Additional settings
Lock screen for cleaning
M31565
MORE
Inside
Preset energy-saving schedules
This thermostat is pre-set with energy-saving program settings for four time periods.
Using the default settings can reduce your heating/cooling expenses if used as directed.
Savings may vary depending on geographic region and usage.
Default Heat Settings Default Cool Settings
WAKE
6:00 am 70 °78 °
LEAVE
8:00 am 62 °85 °
RETURN
6:00 pm 70 °78 °
SLEEP
10:00 pm 62 °82 °
To change the settings, see pages 16–17.

3 33-00133ES—01
Setting up your thermostat
Setting up your Wi-Fi programmable touchscreen thermostat is easy. It is preprogrammed
and ready to go as soon as it is installed and registered.
Install your thermostat.
Connect it to your home wireless network.
Register online for remote access.
Before you begin, you may want to watch a brief installation video.
Use the QR Code®at the front of this guide, or go to
wifithermostat.com/support
2
3
1
Installing your thermostat
You might need the following tools to install this thermostat:
• No. 2 Phillips screwdriver
• Small pocket screwdriver
• Pencil
• Level (optional)
• Drill and bits (3/16” for drywall,
7/32” for plaster) (optional)
• Hammer (optional)
• Electrical tape (optional)
1 Switch OFF power to your
heating/cooling system.
Important! To protect your equipment,
switch OFF the power to your heating/
cooling system at the breaker box or
the system switch.
or
Circuit
breaker
box
Heating/cooling
system power
switch

33-00133ES—01 4
C
C
If you have an older thermostat with a
sealed mercury tube, turn to page ii
for proper disposal instructions.
Terminal
designation
Installing your thermostat
2 Remove old thermostat faceplate
and leave wires connected.
2a Take a picture of the wire
connections for later reference.
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.
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 the 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.
4 Remove wallplate.
Remove the old wallplate from
the wall after all wires have been
labeled and disconnected.
Blank tags
Sticky tag
Terminal
designation
C
C

5 33-00133ES—01
Installing your thermostat
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.
Thermostat
Wallplate (back view)
Finger holds
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
Wallplate

33-00133ES—01 6
Important! The Wi-Fi thermostat requires a C wire to operate. The C, or common, wire
brings 24 VAC power to the thermostat. Many older mechanical or battery operated
thermostats do not require a C wire. If you don’t have a C wire, try:
• Looking for an unused wire that is pushed into the wall. Connect that wire to C and
check that it is connected to the 24 VAC common at your heating/cooling system.
Check the video section at wifithermostat.com
Note: Not all heating/cooling systems label the 24 VAC common C. Check your system
manual or contact the manufacturer to find out which terminal is the 24 VAC common.
View the Alternate Wiring videos at wifithermostat.com/videos
Wiring
For conventional heating/cooling systems (natural gas, oil or electric furnace, air
conditioner), see page 6. See “Glossary” on page 27 for further definition.
For a heat pump system, see page 7. See “Glossary” on page 27 for further
definition.
Installing your thermostat
Wiring (conventional system)
7A Wire the Wi-Fi thermostat to your conventional system.
a Starting with the C Wire, match the sticky tag on the
wire to the terminal labels.
You must have a C wire. See page 6.
b Loosen screw, insert wire on inside edge of
terminal, then tighten screw.
c Verify wire is firmly secured by gently pulling
on wire.
d Repeat steps a–c for all other wires.
e Push any excess wire back into the wall
opening after all wires are installed.
f Continue to page 9.
Labels don’t match? See alternate
wiring key on page 7.
Note: The wiring for your
application might be different
than the wiring from above.
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
Remove metal jumper
only if you have both
Rand RC wires

7 33-00133ES—01
Installing your thermostat
Wiring (heat pump system only)
7B Wire Wi-Fi thermostat to your heat pump.
a Starting with the C Wire, match the sticky tag on the wire to the terminal labels.
You must have a C wire. See page 6.
b Loosen screw, insert wire on inside edge of
terminal, then tighten screw.
c Verify wire is firmly secured by gently pulling
on wire.
d Repeat steps a–c for all other wires.
e Push any excess wire back into the wall
opening after all wires are installed.
f Continue to page 9.
Note: If old thermostat has separate wires on AUX and E,
place both wires into the E/AUX terminal. If old thermostat
has wire on AUX with a jumper to E, place wire on E/AUX
terminal. No jumper is required.
Labels don’t match? See alternate
wiring key on page 8.
Note: The wiring for your
application might be different
than the wiring from above.
MCR33529
RC
R
O/B
Y
G
C
HEAT PUMP
L
E/AUX
K
R
O
G
Y
C
AUX
Y2
W2
K
Y2
W2
RC
R
W
Y
G
C
RC
R
W
Y
G
C
1
2
3
CONVENTIONAL
Metal J
umper
Alternate wiring (conventional system)
Use this if your wire labels don’t match the terminal labels.
Note: You must have
a C wire or equivalent.
See page 6.
Remove metal jumper connecting Rand RC only if you must connect both
Rand RC.
If your old thermostat had both Rand RH wires, remove metal jumper.
Connect the Rwire to the RC terminal, and the RH wire to the Rterminal.
Do not use Kterminal. For future use.
Alternate wiring key (conventional system)
2
3
1

33-00133ES—01 8
Installing your thermostat
Alternate wiring (heat pump system only)
Use this if your wire labels don’t match the terminal labels.
Note: You must have
a C wire or equivalent.
See page 6. RC
R
O/B
Y
G
C
L
E/AUX
K
MCR33530A
Y2
RC
R
O
Y
G
C
1
2
3
3
47
6
5
HEAT PUMP
Metal Jumper
AUX
Alternate wiring key (heat pump system only)
Leave metal jumper between Rand RC terminals in place.
If your old thermostat had both Vand VR wires, check wifithermostat.com for help.
If your old thermostat had separate Oand Bwires, attach the Bwire to the Cterminal. If
another wire is attached to the Cterminal, check wifithermostat.com for help. Attach the Owire
to the O/B terminal. Set System Function 0190 to 0 (see page 22).
If your old thermostat had an Owire and not a Bwire, attach the Owire to the O/B terminal.
If your old thermostat had separate Y1, W1 and W2 wires, check wifithermostat.com for help.
This is the system monitor. If the monitor finds a problem, you will see a red light in the upper
right corner of the thermostat (shines through the cover).
If old thermostat has separate wires on AUX and E, place both wires into the E/AUX terminal. If
old thermostat has wire on AUX with a jumper to E, place wire on E/AUX terminal. No jumper is
required.
Do not use Kterminal. For future use.
2
3
1
4
5
6
7