Honeywell RTH8500 Series User manual

Installation
Guide
RTH8500
Touchscreen Programmable Thermostat
69-1902EF-1

Read and save these instructions.
MERCURY NOTICE: Do not place your old thermostat in the trash if it contains
mercury in a sealed tube. Contact your local waste management authority for
instructions regarding recycling and proper disposal.
Need Help?
For assistance with this product please visit http://yourhome.honeywell.com
or call Honeywell Customer Care toll-free at 1-800-468-1502
® U.S. Registered Trademark.
US Patent No. 6595430, D520,386 and other patents pending.
Copyright © 2007 Honeywell International Inc. All rights reserved.
This thermostat provides control of 24 VAC heating and cooling systems, or
750mV heating systems.
This thermostat contains a Lithium battery which may contain Perchlorate material.
Perchlorate Material—special handling may apply,
See www.dtsc.ca.gov/hazardouswaste/perchlorate

Getting started
Installation tips...........................................2
Pre-installation checklist ........................... 3
Old thermostat removal
Remove old thermostat.............................5
Identify and label wires..............................6
New thermostat installation
Wallplate mounting ....................................7
Wire connections ..................................... 10
Battery installation...................................13
Thermostat mounting ..............................14
Time/date settings ...................................15
System setup
How to change settings...........................16
System settings ..................................17-23
Appendices
In case of difficulty...................................24
Customer assistance ...............................27
Limited warranty ......................................28
Table of contents
RTH8500
1

Installation Guide
2
Installation is easy—even if you’ve never done it before!
Your new thermostat has been designed for fast, easy installation. Just follow the
simple, step-by-step instructions in the following pages.
Install in three simple steps
• Label wires and remove your old thermostat (see pages 5-6).
• Install and wire your new thermostat (see pages 7-15).
• Set your new thermostat to match your heating/cooling system
(see pages 16-23).
Installation tips
• Have everything you need ready to go before you begin (see pages 3-4).
• Do not use wire color as a guide. Use wire labels instead (see page 6).
TURN OFF POWER at heating/cooling system (or fuse/circuit-breaker panel) before you
begin installation.

RTH8500
3
Pre-installation checklist
Check to make sure your package includes the following items:
RTH8500 thermostat
(wallplate attached to back)
Wire labels
Wall anchors and
mounting screws (2 each)
Operating manual

Installation Guide
4
Pre-installation checklist
Required tools & supplies
• No. 2 Phillips screwdriver
• Small pocket screwdriver
• Drill
• Drill bit (3/16” for drywall, 7/32” for plaster)
• Hammer
• Pencil
• Electrical tape
• Level (optional)
• Three fresh AAA alkaline batteries

RTH8500
5
Remove your old thermostat
1. Turn off power at heating/cooling system (or fuse/circuit-breaker panel).
2. Remove cover and thermostat, but leave wallplate with wires attached.
Is there a sealed tube containing mercury?
If so, see inside front cover of this manual
for proper disposal instructions.
Old thermostat
Cover
Leave wallplate in place

Installation Guide
6
Label wires and remove old wallplate
Use a screwdriver to disconnect wires one by one. As you disconnect each wire,
wrap it with the label matching the letter on your old thermostat. (Adhesive labels are
supplied in your thermostat package.)
Remove the old wallplate only after all wires are labeled. Be careful not to let loose
wires fall into the wall opening.
Wrap supplied labels securely around each wire.
Do not let wires fall into wall opening!
IGNORE WIRE COLORS: Use only letter designations to
identify wire types.

RTH8500
7
Remove wallplate
Grasp top and bottom of wallplate and pull to remove from thermostat.
+
++
Wallplate

Installation Guide
8
Mark wallplate mounting position
1. Pull wires through
wallplate.
2. Level wallplate if desired. 3. Mark positions of
both screw holes.

RTH8500
9
Mount wallplate
1. Drill holes at pencil-marked locations:
3/16” holes for drywall
7/32” holes for plaster.
2. Use hammer to tap
anchors into holes until
flush with wall.
3. Place wallplate over
anchors and insert screws.
Check level if desired,
then tighten screws.

Installation Guide
10
Connect wires (typical installation)
1. Match each labeled wire with
same letter on terminal.
(Use HEAT PUMP letters if
you have a heat pump system.)
2. Use a screwdriver to loosen
screw terminals, insert
wires, then tighten screws.
3. Push any excess wire back
into the wall opening.
Remove metal jumper if you have both Rand Rc wires.
Labels don’t match?
If labels do not match letters on
thermostat, see pages 11-12.
Insert wires, then
tighten screws.

RTH8500
11
If labels do not match terminals, connect
wires as shown here (see notes, below).
Remove metal jumper connecting Rand
Rc only if you must connect both Rand
Rc wires.
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.
If your old thermostat had only 1 Cor
C1 wire, connect it to the Cterminal. If
your old thermostat had 2 Cor C1 wires,
wrap each separately with electrical tape
and do not connect them.
Alternate wiring (conventional systems)
RC
R
W
Y
G
C
Y2
W2
Rc
R
W
Y
G
C
Y2
W2
2
3
2

Installation Guide
12
If labels do not match letters on the thermostat,
check the chart at right and connect to terminal
as shown here (see notes, below).
Leave metal jumper in place, connecting
R& Rc terminals.
If your old thermostat had both Vand VR
wires, stop now and contact a qualified
contractor for help.
If your old thermostat had separate Oand B
wires, attach the Bwire to the Cterminal. If
another wire is attached to the Cterminal,
stop now and contact a qualified contractor
for help.
If your old thermostat had Y1, W1 and W2
wires, stop now and contact a qualified
contractor for help.
If Lterminal is used, Cterminal wire must be
connected (contact a contractor if there is
no Cwire).
If Eand Aux terminals do not each have a
wire connected, use a small piece of wire to
connect them to each other.
Alternate wiring (for heat pumps only)
2
3
3
4
5
5
6
6
5
6

RTH8500
13
Install batteries
Install 3 fresh AAA alkaline batteries
in back of thermostat.
Back of thermostat

Installation Guide
14
Remove tab and mount thermostat
TIP: If wires interfere when you try to mount the
thermostat, push excess wire back into the wall opening.
Remove tab.
Align pins on back of thermostat with
slots in wallplate, then push gently until
thermostat snaps into place.

RTH8500
15
Set time/date and restore electrical power
Press s/t
to set date
Press s/t
to set month
Press s/t
to set year
TIP: Don’t forget to restore electrical power at the heating/cooling system,
or at the fuse/circuit-breaker panel.
Press s/t
to set time
Press DONE to save changes Press DONE to save and exit
DONE
TUE
15
6
2006
DONE
TUE
6
PM
1:00

Installation Guide
16
System setup
2. Press and hold
blank center key
until the display
changes.
1. Press SYSTEM.
Press s/t to
select function
Function Setting
Press s/t to
change setting
SCHED HOLD SCREEN MORE
TUE
AM
Following
Schedule
Inside
Outside
Set To
70
6:01
70
43
FAN
AUTO
SYSTEM
HEAT
DONE
TUE
Inside Set To
70
0120
70
20
FAN
AUTO
DONE CANCEL
TUE
AM
Inside Set To
70
6:01
70
FAN
AUTO
SYSTEM
HEAT
3. Change settings as
required (see pages
17-23).
4. Press DONE to exit &
save changes.
NOTE: Because of choices you make while programming, some functions
in the following pages may not appear.

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17
System setup
Year setting (first two digits)
Function
0120 Press s/t to change the first two digits of the year:
Options: 20 = Year 20xx
21 = Year 21xx
Year setting (second two digits)
Function
0130 Press s/t to change the last two digits of the year:
Options: 01 - 99 (i.e., 2001 - 2099)
Month setting
Function
0140 Press s/t to change the current month:
Options: 01 - 12 (i.e., January - December)
Date setting
Function
0150 Press s/t to change the current date:
Options: 01 - 31

Installation Guide
18
Select system type
Function
0170 Press s/t to select your system type:
Options: 1 Heat/cool: Gas, oil or electric heating with central air conditioning.
2 Heat pump: Single-stage heat pump (no backup or auxiliary heat).
3 Heat only: Gas, oil or electric heat without central air conditioning.
4 Heat only with fan: Gas, oil or electric heat without central air conditioning.
5 Hot water heat (no fan): Gas, oil or hot water heat without central air
conditioning.
6 Cool only: Central air conditioning only.
7 Multi-stage heat pump: Heat pump with backup or auxiliary heating.
8 Conventional multi-stage system: 2 heat stages (wires on Wand W2),
2 cooling stages (wires on Yand Y2).
9 Conventional multi-stage system: 2 heat stages (wires on Wand W2),
1 cooling stage (wire on Y).
10 Conventional multi-stage system: 1 heat stage (wire on W), 2 cooling
stages (wires on Yand Y2).
System setup