Honeywell RTH5100B User manual

Owner’s Manual
Read and save these
instructions.
For help please visit
yourhome.honeywell.com
RTH5100B
Non-Programmable
Digital Thermostat
Installation is Easy
1. Label wires and remove your old thermostat
2. Install and wire your new thermostat
3. Set your new thermostat to match your heating/cooling system
• It is preset for the most common system
Do you need assistance? We are here to help.
Call 1-800-468-1502 for wiring assistance before returning
the thermostat to the store.
This thermostat works on 24 volt or 750 mV systems.
It will NOT work on multi-stage heat pump systems or
120/240 Volt systems.

2
NOTICE: To avoid possible compressor damage, do not run air
conditioner if the outside temperature drops below 50°F (10°C).
ATTENTION: MERCURY RECYCLING NOTICE
This product does not contain mercury. However,
this product may replace a product that contains
mercury. Mercury and products containing
mercury should not be discarded in household
trash.
For more information on how and where to
properly recycle a thermostat containing
mercury in the United States, please refer to the
Thermostat Recycling Corporation at
www.thermostat-recycle.org.
For mercury thermostat recycling in Canada,
please refer to Switch the Stat at
www.switchthestat.ca
NO MERCUR
Y
NE PAS JETER
LE MERCURE
Hg
M28300
Customer assistance
For assistance with this product, please visit
http://yourhome.honeywell.com.
Or call Honeywell Customer Care toll-free at
1-800-468-1502.
To save time, please note your model number
and date code before calling.
Remove battery holder; model number is on
the battery holder.
® U.S. Registered Trademark. Patents pending.
US Patent No. D535,573 and other patents pending.

3
Installation
Installation............................................3
Advanced Installation...........................7
About your new thermostat
Controls and Home screen
quick reference.....................................9
Compressor protection.......................12
Replace batteries...............................12
Appendices
Troubleshooting..................................13
Limited warranty.................................14
Table of contents
1 Turn Off Power to Heating/Cooling System
or
M31535
Circuit breaker
box Heating/cooling system power switch
2 Remove Old Thermostat
Remove old thermostat but leave wallplate with wires attached.
Do not remove wallplate yet
C
C
MCR33823
Terminal
designation
If you have an older thermostat with a
sealed mercury tube, turn to page 2
for proper disposal instructions.

4
3 Label Wires with Tags
Label the wires using the supplied wire labels as you disconnect them.
M28100
5 Mount Wallplate
Mount the new wallplate using the included screws and anchors.
Drill 3/16-in. holes for drywall
Drill 3/32-in. holes for plaster
MCR29533
4 Separate Wallplate from New Thermostat
Remove wallplate from the new thermostat and mount onto wall.
M29532
Wallplate
Wire Labels
Terminal designation
C
C
MCR31537

5
Remove metal
jumper if you
have both Rand
Rc wires.
MCR29534
Thermostat does not work on Heat Pumps with auxiliary/backup heat.
We are here to help. Call 1-800-468-1502 for wiring assistance.
6 Connect Wires
Simply match wire labels.
If labels do not match letters on the thermostat, check “Alternate Wiring” on
page 5 and connect to terminal as shown (see notes, below).
Alternate Wiring
If wires will be connected to both
Rand Rc terminals, remove metal
jumper
Do not connect both Oand B, If
you have a heat pump. Connect
O wire to O/B W. Wrap B wire with
electrical tape and do not use.
Do not use C, X or B. Wrap bare
end of wire with electrical tape.
Rc
R
Y
NOT
USED
O/B W
G
DO
NOT
CONNECT
MCR29548
C
Rc
R
W
Y
G
OR R
OR RH 4V
OR Y1 M
OR W1 H O
B
OR F
OR X B

6
7 Install Batteries
Install two AAA alkaline batteries.
8 Install Thermostat onto
Wallplate
Install thermostat onto the wallplate on
the wall.
Back of thermostat
MCR29535
MCR29536
M31544
or
Circuit breaker box Heating/cooling system
power switch
9 Turn Power Back On
Turn the power back on to the
heating/cooling system.

7
10 If your system type is...
If your system type is:
qSingle Stage Heat and Cool
Congratulations, you’re done!
If your system type is:
qHeat Pump* without Backup Heat
qHeat Only
Continue with Advanced Installation to match your thermostat to your system
type.
*Heat Pump—an air conditioner that provides cooling in the summer, and also
runs in reverse in the winter to provide heating.
If you are not sure of your system type or if you have other
questions, call us toll-free at 1-800-468-1502.
This thermostat works on 24 volt or 750 mV systems. It will NOT work on multi-
stage heat pump systems or 120/240 Volt systems.
Advanced Installation
Enter System Setup
To enter system setup, press and hold both
the sand FAN buttons until the display
changes (approximately 5 seconds).
Changing Settings
1. Press the sor tbutton to change the
setting.
2. Press NEXT to advance to the next
function.
3. Press DONE to exit and save settings.
MCR29537
Function Setting
Next
1
0
Done
MCR29538

8
Function
Description
Press the sor tbutton to Setting
1 select the type of system you
have in your home
0 Heating and cooling: Gas, oil or electric heating with
central air conditioning.
1 Heat pump: Outside compressor provides both heating
and cooling.
2 Heating only: Gas, oil or electric heating without central
air conditioning.
3 Heating only with fan: Gas, oil or electric heating
without central air conditioning. (Use this setting if you
could turn the fan on and off with a fan switch on your
old thermostat.)
2 select whether your
changeover valve is used in
heating or cooling
0 Cooling changeover valve: Use this setting if you
connected a wire labeled “O” to the O/B W wire terminal.
1 Heating changeover valve: Use this setting if you
connected a wire labeled “B” to the O/B W wire terminal.
3 select your heating system
and fan operation
0 Gas or oil heat: Use this setting if you have a gas or oil
heating system (system controls fan operation).
1 Electric heat: Use this setting if you have an electric
heating system (thermostat controls fan operation).
5 select your heating system
and optimize its operation
5 Gas or oil furnace: Use this setting if you have a
standard gas or oil furnace that is less than 90%
efcient.
9 Electric furnace: Use this setting if you have any type
of electric heating system.
3 Hot water or high-efficiency furnace: Use this setting
if you have a hot water system or a gas furnace of
greater than 90% efciency.
1 Gas/oil steam or gravity system: Use this setting if
you have a steam or gravity heat system.
12 select Manual or Auto
Changeover
0 Manual Changeover: (Heat/Off/Cool)
1 Automatic Changeover: (Heat/Off/Cool/Auto)
Automatically turns on heat or cool based on room
temperature.
CAUTION: To avoid possible compressor
damage, do not use Auto Changeover if the
outside temperature drops below 50 ºF (10 ºC).
NOTE: System maintains a minimum 3 ºF
difference between heat and cool settings.
14 select Fahrenheit or Celsius
temperature display
0 Fahrenheit temperature display (°F)
1 Celsius temperature display (°C)
27 select maximum heat
temperature setting
40 – 90 Maximum heat temperature setting (°F)
(4.5 to 31.5°C)
28 select minimum cool
temperature setting
50 – 99 Minimum cool temperature setting (°F)
(10.5 to 37°C)

9
Thermostat controls
M28301
Digital display Battery holder
Temperature buttons
Press to adjust
temperature settings.
Function buttons
Press to select the function displayed just above each button.
(Functions change depending on the task.)
About your new thermostat
Your new Honeywell thermostat has been designed to give you many years of
reliable service and easy-to-use, push-button climate control.
• Large, clear, backlit display is easy to read — even in the dark.
• Displays both room temperature and temperature setting.
• Removable battery holder for fast, easy replacement.
• Built-in compressor protection.

10
System
Cool
Cool On
Setting
Cool
Inside
72
72
Auto
Fan
M28305
Adjust the temperature
Press sor tto adjust the
temperature.
NOTE: Make sure the thermostat
is set to the system you want to
control (heat or cool).
Display screen
System
Cool
Cool On
Setting
Cool
Inside
72
72
Auto
Fan
M28302
Current inside temperature Temperature setting
System status
Indicates system is on.
(Cool On or Heat On.)
System setting
Press the SYSTEM
button to select Heat,
Cool or Off.
Fan setting
Press the FAN button to
select Auto or On.
In “Auto” mode (the most
commonly used setting), the fan
runs only when the heating or
cooling system is on. If set to “On,”
the fan runs continuously.
• Heat: Thermostat controls only the heating
system.
• Cool: Thermostat controls only the cooling
system.
• Auto: Thermostat automatically selects
heating or cooling depending on the
indoor temperature.
• Off: Heating and cooling systems are off.