Honeywell RTH8500 Series User manual

Installation
Guide
RTH8500
Touchscreen Programmable Thermostat
69-1902ES-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 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

1
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

Installation Guide
2
About your new thermostatInstallation 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
About your new thermostatPre-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
About your new thermostatPre-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
About your new thermostatRemove 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
About your new thermostatLabel 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
About your new thermostatRemove wallplate
Grasp top and bottom of wallplate and pull to remove from thermostat.
+
++
Wallplate

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