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q Wrap the wires around a pencil to prevent  
RTH230B  
Programmable Electronic Thermostat  
Installation and User Guide  
them from falling into the wall.  
r If the hole in the wall is too big, insulate it  
using a non-flammable material in order to  
avoid air draughts behind the thermostat.  
2
.2 Installing the New Baseplate  
1
. Introduction  
For a new installation, choose a location approximately 5 feet  
(1.5 m) above the floor and on an inside wall. Avoid draughty  
areas (top of staircase, air outlet, etc.), dead air spots (behind  
doors), direct sunlight or areas near concealed pipes or chim-  
neys.  
The RTH230B programmable thermostat can be used to control:  
a gas, fuel oil or electric furnace - 2 or 3 wires  
a central air conditioner - 2 or 3 wires  
a hot water system with or without pump - 2 wires  
a millivolt system - 2 wires  
a central heating and cooling system - 4 or 5 wires  
Note: These thermostats are not compatible with heat pumps or  
multi-stage systems.  
Adjustment  
buttons  
Display  
n Remove the thermostat faceplate.  
o Loosen the locking screw to separate the thermostat from its  
baseplate (the screw cannot be completely removed).  
Programming  
buttons  
System operating  
mode selector  
Fan operating  
mode selector  
Features  
p Tilt the thermostat upwards.  
System operating mode selection: heat, cool or off  
q Mark and bore the appropriate mounting holes (or use the  
Fan operating mode selection: automatic or on (continuous)  
existing holes). Insert the plastic anchors.  
Programmable heating and cooling cycle lengths: 10, 12, 15, 20  
or 30 minutes  
r Pass the wires through the opening of the baseplate and fix the  
baseplate to the wall using the screws provided.  
Temperature display in °F or °C  
Battery replacement indicator  
5-2 programming including:  
2
.3 Connecting the Thermostat  
The connection of the new thermostat should be similar to that of  
the old thermostat; however, it can vary depending on the installa-  
tion.  
-
-
-
-
Preprogrammed energy-saving schedule  
Early Start  
Temporary bypass  
Time display (12 h or 24 h)  
Rh  
Rc  
W
Y
Heating power supply  
Cooling power supply  
Heating signal  
Cooling signal  
Fan  
Filter replacement indicator  
2
. Installation  
G
2
.1 Removing the Old Thermostat  
Note: The red jumper wire between the Rc and Rh terminals must  
be removed in 2- or 5-wire installations. The jumper must be used in  
IN ORDER TO AVOID ANY RISK OF ELECTRIC SHOCK, CUT  
POWER TO THE HEATING SYSTEM.  
3- or 4-wire installations if you wish to use the mode selector switch  
n Remove the old thermostat to access the wires.  
for the fan.  
Warning: If the old thermostat was mounted onto an electrical box,  
it was probably powered by 120/240 volts. In this case, this thermo-  
stat cannot be used.  
o Identify and label each wire (with the corresponding letter on  
the wire terminal) and remove them from the terminals.  
69-1800-01  
p If necessary, strip the end of each wire (maximum of 1/4 inch).  
RTH230B  
69-1800-01 11/09 1/4  
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2
2
.3.1 2-wire Heating  
2.4 Setting J2 Jumper  
The jumper defines the fan operation when the fan is placed in auto-  
matic mode.  
Use this setting if you have an electric furnace. In  
this setting, when the fan is placed in automatic  
mode, it works only when heating or cooling is  
activated.  
J2 jumper  
HE  
Heat relay  
Use this setting if you have a gas or fuel oil fur-  
nace. In this setting, when the fan is placed in  
automatic mode, it works as follows:  
.3.2 2-wire Cooling  
When the thermostat is placed in cool mode,  
the fan works only when cooling is activated.  
HG  
When the thermostat is placed in heat mode,  
the fan is controlled by the furnace fan control  
circuitry.  
2
.5 Installing the Batteries  
Cool relay  
2
.3.3 3-wire Heating  
n Pull out the battery cover.  
o Install the batteries as shown. Observe the polarity.  
p Reinstall the battery cover. You will hear a clicking sound.  
After the batteries are installed, the thermostat performs a series of  
tests for approximately 5 seconds.  
Heat relay  
Fan relay  
Afterwards, the screen displays the actual  
temperature. It is normal that the displayed  
temperature be higher than the ambient  
2
.3.4 3-wire Cooling  
temperature if you are holding the thermo-  
stat. The thermostat will display the ambient temperature once it is  
installed on the wall. By default, the setpoint is 70°F (21°C).  
2
.6 Completing the Installation  
Cool relay  
Fan relay  
2
.3.5 4-wire Heating and Cooling  
n Once the baseplate and the batteries are installed, mount the  
thermostat on the baseplate.  
o Secure the thermostat using the locking screw and install the  
faceplate.  
Heat relay  
Cool relay  
p Apply power back to the system.  
Fan relay  
3. Basic Functions  
3.1 System Operating Mode  
2
.3.6 5-wire Heating and Cooling  
Use the selector switch to place the system in Heating  
mode (HEAT) or Cooling mode (COOL), or to set the  
system off.  
Note: When you place the thermostat in Cooling mode, you might need to  
wait up to five minutes before cooling can start. This is a safety feature for  
Fan relay  
the compressor.  
will flash on the screen until cooling can start again.  
Heat relay  
Cool relay  
RTH230B  
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3
.2 Fan Operating Mode  
3.7 Battery Replacement Indicator  
Use the selector switch to set the fan to automatic  
mode (AUTO) or continuous mode (ON).  
An icon appears when the batteries need replacement.  
This icon will flash for 120 days, then the thermostat  
will cut power to the heating/cooling unit. The icon dis-  
appears once the batteries are replaced.  
Note: This switch is not used if you have a 2-wire  
installation as the fan is not connected to the thermo-  
stat.  
After replacing the batteries, readjust the time and day (see section  
5
.1). However, the temperature and program settings are saved and  
If you have an electric furnace (see section 2.4), the fan  
works only when heating or cooling is activated.  
do not need to be re-entered.  
Warning: Before removing the batteries, place the  
system switch on the thermostat to Off. Otherwise, the  
heating/cooling unit might still be running even after  
the batteries are removed.  
If you have a gas or fuel oil furnace (see section 2.4), the fan  
works as follows:  
AUTO  
When the thermostat is placed in cool mode, the fan  
works only when cooling is activated.  
When the thermostat is placed in heat mode, the fan is  
controlled by the furnace fan control circuitry.  
4
. Configuration Menu  
ON  
The fan is always on.  
n To access the configuration menu, press both  
buttons  
3
.3 Displaying the Temperature  
simultaneously for 3 seconds.  
The actual temperature is normally displayed. To view the setpoint,  
press once on one of the buttons. The setpoint is displayed for  
seconds along with the icon.  
o To go to the next parameter (menu item), briefly press both  
buttons simultaneously.  
5
p To modify a parameter, press one of the  
q Repeat steps 2 and 3 if necessary.  
buttons.  
Note: Pressing either of the  
buttons more than once will  
change the setpoint.  
r Press both  
buttons simultaneously for 3 seconds to exit  
the configuration menu.  
3
.4 Setting the Temperature  
Press one of the  
played.  
buttons until the desired temperature is dis-  
DISPLAY DESCRIPTION  
Temperature display  
Time display  
DEFAULT  
°F  
OPTIONS  
°C or °F  
3
.5 Thermostat Control Mode  
12 h  
12 h or 24 h  
On or Off  
3
.5.1 Manual/Permanent Hold Mode  
Early Start 1  
Off  
Maintains the temperature at a fixed setpoint. To place the thermo-  
stat in this mode, press [ Mode ]. The house icon will disappear.  
Heating cycles per hour 2  
2, 3, 4, 5 or 6 3  
4
4
3
.5.2 Programmable Mode  
Cooling cycles per hour 2  
2, 3, 4, 5 or 6 4  
Maintains the temperature according to the energy-saving sched-  
ule. To place the thermostat in this mode, press [ Mode ]. The cur-  
rent period will be displayed. The four possible periods are:  
1
When Early Start is On, the thermostat determines when to start heating  
or cooling so that the desired temperature is reached at the set time.  
2
When either the heating or cooling parameter is displayed, use the sys-  
tem mode selector switch to alternate between the two parameters.  
3
For optimal heating control, use the setting that matches your system as  
Wake up  
Leave for work  
Return home  
Sleep  
follows: 2=30 min (steam, gravity), 3=20 min (hot water, 90%+ high-effi-  
ciency furnace), 4=15 min (gas or oil), 5=12 min (alternate setting for gas  
or oil), 6=10 min (electric).  
To see the default settings of each period, see section 5.2.  
Temporary Bypass  
4
The corresponding cooling cycle lengths are as follows: 2=30 min,  
If you modify the temperature (using the  
buttons) when the  
3=20 min, 4=15 min, 5=12 min, 6=10 min  
thermostat is in programmable mode, the new temperature will be  
used for the next 2 hours. The house icon flashes during the  
bypass. At the end of the bypass period, the thermostat returns to  
the temperature settings of the period currently underway.  
5
. Programming  
3
.6 Filter Replacement Indicator  
5.1 Setting the Time and Day  
After 500 hours of operation, an icon appears to indi-  
cate that the filter needs replacement. Once the filter  
is replaced, press [ Filter ] for 3 seconds to remove  
n Press [ Clk ]. The hour flashes.  
o Set the hour using  
p Press [ Clk ]. The minutes flash.  
q Set the minutes using  
r Press [ Clk ]. The day flashes.  
.
the icon and reset the counter.  
.
s Set the day using  
.
t Press [ Exit ] to exit.  
RTH230B  
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5
.2 Energy-saving Schedule  
6
. Technical Specifications  
Your thermostat is preprogrammed with an energy-saving schedule.  
The schedule automatically controls your heating or cooling system  
by switching from one setpoint to the next according to the preset  
times.  
Power supply: 2 AA batteries  
Maximum load: 1 A @ 24 Vca per output  
Setpoint range (heating): 41 to 82°F (5 to 28°C)  
Setpoint range (cooling): 59 to 95°F (15 to 35°C)  
Display range: 23 to 122°F (-5 to 50°C)  
Storage temperature: -2 to 122°F (-20 to 50°C)  
Temperature display resolution: 1°F (0.5°C)  
Accuracy: ± 1°F (0.5°C)  
Heating/cooling cycle lengths: 10, 12, 15, 20 or 30 minutes (programmable)  
Compressor short-cycle protection (minimum off time): 5 minutes  
Data memory: non-volatile  
Monday  
to Friday  
Saturday  
& Sunday  
Default schedule settings  
Heating  
70°F (21°C)  
6
8
6
:00 a.m.  
:00 a.m.  
:00 p.m.  
6:00 a.m.  
Cooling 78°F (25.5°C)  
Heating 62°F (16.5°C)  
Cooling 85°F (29.5°C)  
--  
--  
Dimensions: 5 in. x 3 in. x 1 in. (127 mm x 75 mm x 28 mm)  
Heating  
70°F (21°C)  
Cooling 78°F (25.5°C)  
Heating 62°F (16.5°C)  
7. Warranty  
Honeywell warrants this product, excluding battery, to be free from defects in  
the workmanship or materials, under normal use and service, for a period of  
one (1) year from the date of purchase by the consumer. If at any time dur-  
ing the warranty period the product is determined to be defective or malfunc-  
tions, Honeywell shall repair or replace it (at Honeywell's option).  
If the product is defective,  
1
0:00 p.m.  
10:00 p.m.  
Cooling  
82°F (28°C)  
Note: To use the schedule, place the thermostat in programmable  
mode.  
5
.3 Modifying the Schedule  
(i) return it, with a bill of sale or other dated proof of purchase, to the place  
from which you purchased it, or  
You can program up to 4 periods per day, each period having its  
own temperature settings. The same program is repeated daily from  
Monday through Friday and another program is used for Saturday  
and Sunday. For each period, you can set the start time, the heating  
setpoint and the cooling setpoint.  
(
ii) call Honeywell Customer Care at 1-800-468-1502. Customer Care will  
make the determination whether the product should be returned to the  
following address: Honeywell Return Goods, Dock 4 MN10-3860,  
1885 Douglas Dr N, Golden Valley, MN 55422, or whether a replace-  
ment product can be sent to you.  
This warranty does not cover removal or reinstallation costs. This warranty  
shall not apply if it is shown by Honeywell that the defect or malfunction was  
caused by damage which occurred while the product was in the possession  
of a consumer.  
n Press [ Pgm ]. The settings for period 1 are displayed.  
Period start time  
Temperature  
setting  
Honeywell's sole responsibility shall be to repair or replace the product  
within the terms stated above. HONEYWELL SHALL NOT BE LIABLE FOR  
ANY LOSS OR DAMAGE OF ANY KIND, INCLUDING ANY INCIDENTAL  
OR CONSEQUENTIAL DAMAGES RESULTING, DIRECTLY OR INDI-  
RECTLY, FROM ANY BREACH OF ANY WARRANTY, EXPRESS OR  
IMPLIED, OR ANY OTHER FAILURE OF THIS PRODUCT. Some states do  
not allow the exclusion or limitation of incidental or consequential damages,  
so this limitation may not apply to you.  
Program days  
Period number  
Note: During programming, to skip a period, press [ CLR ] while  
the period is displayed. For example, in the predefined energy-sav-  
ing schedule, periods 2 and 3 have been skipped for Saturday and  
Sunday.  
THIS WARRANTY IS THE ONLY EXPRESS WARRANTY HONEYWELL  
MAKES ON THIS PRODUCT. THE DURATION OF ANY IMPLIED WAR-  
RANTIES, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND  
FITNESS FOR A PARTICULAR PURPOSE, IS HEREBY LIMITED TO THE  
ONE-YEAR DURATION OF THIS WARRANTY. Some states do not allow  
limitations on how long an implied warranty lasts, so the above limitation  
may not apply to you.  
o Select the program using the [ Day ] button (MO TU WE TH FR  
appears when the Monday-Friday program is selected or SA  
SU appears when the Saturday/Sunday program is selected).  
Press for 3 seconds to select all 7 days.  
p Set the time (in increments of 15 minutes) using the  
tons.  
but-  
This warranty gives you specific legal rights, and you may have other rights  
which vary from state to state.  
q Press [ P# ]. The heating or cooling setpoint  
flashes depending on the position of the Heat/  
Cool selector.  
If you have any questions concerning this warranty, please write Honeywell  
Customer Relations, 1985 Douglas Dr, Golden Valley, MN 55422 or call 1-  
800-468-1502. In Canada, write Retail Products ON15-02H, Honeywell Lim-  
ited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V4Z9.  
r Set the desired temperature for the displayed  
period using the  
buttons.  
8
. Customer Assistance  
s Use the Heat/Cool selector to switch to the other mode (e.g., if  
you were in Heating mode, switch to Cooling mode). The set-  
point for that mode flashes.  
If you have any questions about the operation of your thermostat, please go  
to www.honeywell.com/yourhome, or call Honeywell Customer Care toll-  
free at 1-800-468-1502.  
t Set the desired temperature using the  
u Press [ P# ] to go to the next period.  
buttons.  
v Repeat steps 2 to 8 for each of the remaining periods.  
w Press [ Exit ] to exit.  
Note: To use the schedule, place the thermostat in programmable  
mode.  
®
As an ENERGY STAR partner, Honeywell has determined that this  
product meets the ENERGY STAR guidelines for energy efficiency.  
Printed in USA  
RTH230B  
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