Honeywell Thermostat CM721 User Manual

CM721..................................2-6  
CM727................................7-11  
USER GUIDE  
 
SETTING-UP THE CM721  
Getting Started’  
This section shows you how to setup and run the thermostat in 3 simple steps:  
STEP 1: Installing the Batteries  
Note: Please follow the instructions in this section only if the thermostat screen is blank (no  
symbols or digits are displayed). If the room temperature is already displayed move on to Step 2:  
Setting the Date and Time.  
To install the Batteries:  
a. Lift up the front cover of the thermostat to reveal the battery cover and product controls.  
b. Remove the battery cover by pressing down and sliding out.  
c. Insert the 2 x AA LR6 Alkaline Batteries supplied with the thermostat, ensuring the correct  
orientation (see ‘Controls Layout’ on page 2).  
d. After a short pause the thermostat will display information on the screen and is now ready for use.  
e. Replace the battery cover by sliding it firmly back into the front of the thermostat.  
STEP 2: Setting the Date and Time  
To set the Date and Time:  
a. Press the DATE button to begin setting the date. When you set  
the date for the first time after the batteries are inserted, the  
display will show:  
Press the  
or buttons to set the current day of the month  
(e.g. d 01 = 1st day of the month) then press the green  
button to confirm.  
b. Press the  
year (e.g. m 01 = January) then press the green  
or  
buttons to set the current month of the  
button to  
confirm.  
c. Press the  
= 2006) then press the green  
or  
buttons to set the current year (e.g. yr 06  
button to confirm.  
The date is now stored.  
d. Use the  
the green  
or  
buttons to set the correct time then press  
button to confirm. Each press of the buttons will  
change the time by one minute and holding them down will  
change the time slowly at first and get progressively quicker.  
AM  
Note: If this mode is entered accidentally then press the  
AUTO, MAN or OFF buttons to exit.  
STEP 3: Running the Built-in Heating Program  
The thermostat is now ready for operation. Press the AUTO button and the built-in heating program  
will start running. Note: The built-in heating program has been designed to provide normal comfort  
requirements, but if you want to customise the settings please see the next section ‘Programming  
the CM721’.  
3
 
‘Efficient Daily Use’  
PROGRAMMING THE CM721  
The Built-in Heating Program  
The built-in heating program has 4 temperature level changes that can be set between 3.00am  
and 2.50am the following day - allowing you to maintain the evening temperature after midnight.  
Each temperature level can be set between 5°C and 35°C, and adjusted in 0.5°C increments. The  
factory default program for heating is as follows.  
Period  
1
2
3
4
Time  
6:30  
21°C  
8:00  
18°C  
18:00  
21°C  
22:30  
16°C  
Temperature  
Reviewing the Heating Program  
To review or edit the heating program use the PROGRAM  
or  
buttons to navigate between  
the 4 individual programming periods.  
Modifying the Heating Program  
To change the heating program:  
a. Press either of the PROGRAM  
enter the programming mode. The time / temperature  
settings for period will be flashing as shown. The  
active period is highlighted by flashing square  
around the numbers at the bottom of the screen.  
or  
buttons to  
1
a
1
2
3
4
b. To adjust the period start time use the or buttons, the display will stop flashing and the  
‘OK?’ indicator will be displayed. Holding the button down will change the time quickly.  
Note: If you are pressing the or buttons and the display flashes the next period, it  
means the next period will be pushed forward.  
c. Once the required time is reached press the green  
button to confirm.  
Note: If the original time setting did not require adjustment press the green  
to step ‘d’.  
button to move  
or  
d. The temperature setting for period  
1
will now be flashing. To adjust this press the  
button.  
buttons and confirm the setting again by pressing the green  
e. The next time and temperature period will now be active. Adjust this by repeating steps b - d  
above until all 4 periods are set or press the AUTO button to run the program as set, at any time.  
Disabling / Enabling Time Periods  
The thermostat has 4 periods that can be programmed, but you may not need all of these switch  
points for your heating requirements. Therefore, any period from 2 to 4 can be removed from (or  
returned to) the heating program profile.  
To disable or enable time periods:  
a. To disable unwanted periods go to the desired period ( 2 to 4 ) using the PROGRAM  
or  
buttons to navigate, ensure the correct period is highlighted with the flashing square symbol.  
Press and hold the button for at least 2 seconds and the display will indicate the period has  
been removed from the program.  
b. To enable periods again follow the same procedure as above, navigating to the already disabled  
period. To enable this period again press and hold the button for at least 2 seconds.  
4
 
OPERATING THE CM721  
‘Using the Features’  
Choosing the Operating Mode  
The thermostat can operate in three different modes: Automatic, Manual or Off. To set the operating  
mode press either of the AUTO, MAN or OFF buttons. The screen indicates which mode is  
currently active by displaying AUTO, MAN or OFF.  
AUTO (automatic) mode sets the thermostat to follow the built-in temperature program (default  
or personalised). Operating the thermostat in this mode is the best way to maintain a high level  
of temperature comfort whilst maximising your energy savings.  
MAN (manual) mode sets the thermostat to act as  
throughout the day. The setpoint can be adjusted from 5°C to 35°C by using the  
a
simple thermostat with  
a
fixed setpoint  
or buttons.  
The thermostat will continue to maintain this temperature until another operating mode or temperature  
is selected.  
OFF mode sets the thermostat to control to a minimum temperature setting of 5°C (default) that  
acts as a frost protection measure for your home.  
During Normal Operation  
Temperature Enquiry  
In AUTO, MAN and OFF operating modes the thermostat will display the current room  
temperature. To review the programmed ‘target’ temperature (the temperature which the  
thermostat is trying to maintain) press the  
button. This ‘target’ temperature value will be  
displayed flashing for 5 seconds before returning to the current room temperature value.  
Temperature Override  
During normal operation (AUTO mode) the programmed temperature can be adjusted manually  
by pressing the  
flash for 5 seconds - during this time the  
Note: This temperature override is cancelled at the next programmed temperature change.  
or buttons or the button. The ‘target’ temperature will be displayed and  
or buttons can be used to modify the set value.  
Adjusting the Time  
To adjust only the time during normal operation use the  
or  
buttons to adjust the time and  
press the green  
button again to confirm any changes.  
Using the Special Features  
SERVICE indicator  
Note: This option only works if activated by your  
installer.  
The 'SERVICE' indicator is displayed at set intervals  
as a reminder that your heating system requires a  
routine check. Please call your installer to arrange a  
maintenance visit.  
The ‘SERVICE’ indicator will remain on the display  
of the CM721 until it is either reset or disabled by  
your installer. The CM721 and heating system will  
continue to operate as normal.  
5
 
‘Using the Features’  
OPERATING THE CM721  
Automatic Summer/Winter Time Change  
The CM721 has a built-in Automatic Summer/Winter Time Change feature that will automatically  
adjust the clock forward or backward by one hour for ‘Daylight Saving Time’. This is carried out  
on the last Sunday of March and October each year.  
Optimum Start  
Optimum Start is a program which ensures that the optimum temperature conditions are  
achieved at the required times. This is an Energy Efficiency feature that adjusts the start time  
of your heating system depending upon how cold it is. For example, on cold days your heating  
system will be started earlier to ensure that your home is warm when you get up (at the target  
temperature) and on warmer days the heating system will be started later to save energy. So,  
if the Optimum Start Feature is used, then the time / temperature settings which are entered  
into the thermostat should be set to when you want to be warm by and not when you want the  
heating system to start.  
FAQ’s  
How do I change the batteries on the  
thermostat when they run out?  
BDR91 Relay Box Controls Layout  
The relay box will normally be found mounted  
close to the boiler.  
The thermostat constantly monitors the battery  
power level, which typically lasts for about  
years before needing replaced. When the power  
is running low flashing symbol will be  
2
a
displayed on the screen. To change the batteries  
follow the steps in the above section (‘STEP 1:  
Installing the Batteries’ on page 3), replacing  
the used batteries with new ones in Step c.  
Note: While changing the batteries your program  
settings will be stored but you may need to adjust  
the time settings to be correct.  
Push button  
and relay  
status LED’s  
What does it mean when the BDR91  
relay box green LED is ON?  
How do I set one temperature for the  
whole day?  
The green LED indicates normal operation of  
the radio frequency system. When the green  
LED is ON the boiler is also ON. When the LED  
is OFF the boiler is OFF.  
To operate as a simple thermostat with one  
temperature throughout the day, select the  
manual operating mode by pressing the  
MAN button. Adjust the temperature by  
pressing the  
or  
buttons - this can be  
set anywhere from 5°C to 35°C in 0.5°C steps.  
The thermostat will continue to maintain this  
temperature until another operating mode is  
selected or the temperature is adjusted.  
When do I need to use the push  
button?  
You should use the push button to control your  
boiler only when the RF communication is lost  
(see the Troubleshooting Guide).  
6
 
TROUBLESHOOTING THE CM721  
Symptom  
Remedy  
Blank Display (Power Loss).  
Check batteries are installed by removing the battery  
cover.  
Check batteries have been installed in the correct  
orientation.  
Replace the batteries.  
Display shows flashing  
symbol.  
The batteries in the thermostat are low on power  
- Replace the batteries.  
Display shows  
symbol.  
A fault has occurred in your heating system. Remove  
and re-insert the batteries.  
If the  
symbol does not clear after a few minutes  
contact your installer.  
Display shows the word 'SERVICE'  
Your installer has set a scheduled maintenance alert  
period on your CM721 as a recommendation that your  
heating system should receive a routine inspection.  
Call your installer to arrange a maintenance visit.  
Note: The CM721 and heating system will continue to  
operate as normal.  
BDR91 red LED is constantly on  
or flashing  
RF communication lost due to the wrong location of  
the room unit - Hook the room unit back on the wall  
bracket where RF communication was reliable.  
Call installer  
NOTE: You can control the boiler manually when the  
RF communication is lost: Press the BDR91 push  
button to switch the boiler on and off. When the green  
LED is on – the boiler is on.  
7
 
CM727 - USER GUIDE  
Description  
Features  
The Honeywell CM727 is  
programmable room thermostat  
designed to control your heating  
a
Ergonomic user interface featuring an ‘OK-button’.  
Large LCD (Liquid Crystal Display) Screen.  
7-day heating program to match your lifestyle, whilst  
maximising energy savings.  
4 independent temperature levels per day (from 5°C to 35°C).  
Holiday button saves energy by letting you reduce the  
temperature for 1 to 99 days.  
Automatic Summer/Winter Time Change.  
Optimum Start to achieve the right temperature at the  
right time.  
system  
efficiently,  
providing  
comfortable temperatures when  
you are at home and energy  
savings when you are away. The  
following instructions explain how  
to program and use the thermostat  
to provide the most home comfort  
at the least cost.  
Built-in Memory holds the user program indefinitely.  
Controls Layout  
1
2
3
4
5
6
17  
7
8
CM727  
1
2
3
4
5
6
7
DATE/  
DAY  
16  
AUTO  
COPY  
DAY  
15  
AUTO  
MAN  
OFF  
14  
9
PROGRAM  
1. . 4  
13  
12  
10  
11  
LCD Screen  
Temperature Change Buttons  
Temperature Enquiry Button  
Operating Mode Buttons  
Green OK Button  
Holiday Function Button  
Program Buttons  
1
2
3
4
5
6
7
8
13  
14  
15  
16  
17  
Battery Low Indicator  
Time Display  
Copy Day Button  
9
Burner On Indicator  
Day Indicator  
Set Date/Day Button  
Time Change Buttons  
10  
11  
12  
Battery Compartment  
Battery Cover  
Temperature Display  
8
 
SETTING-UP THE CM727  
Getting Started’  
This section shows you how to setup and run the thermostat in 3 simple steps:  
STEP 1: Installing the Batteries  
Note: Please follow the instructions in this section only if the thermostat screen is blank (no  
symbols or digits are displayed). If the room temperature is already displayed move on to Step 2:  
Setting the Date and Time.  
To install the Batteries:  
a. Lift up the front cover of the thermostat to reveal the battery cover and product controls.  
b. Remove the battery cover by pressing down and sliding out.  
c. Insert the 2 x AA LR6 Alkaline Batteries supplied with the thermostat, ensuring the correct  
orientation (see ‘Controls Layout’ on page 8).  
d. After a short pause the thermostat will display information on the screen and is now ready for use.  
e. Replace the battery cover by sliding it firmly back into the front of the thermostat.  
STEP 2: Setting the Date and Time  
To set the Date and Time:  
a. Press the DATE/DAY button to begin setting the date. When  
you set the date for the first time after the batteries are inserted,  
the display will show:  
Press the  
or buttons to set the current day of the month  
(e.g. d 01 = 1st day of the month) then press the green  
button to confirm.  
b. Press the  
year (e.g. m 01 = January) then press the green  
or  
buttons to set the current month of the  
button to  
confirm.  
c. Press the  
= 2006) then press the green  
or  
buttons to set the current year (e.g. yr 06  
button to confirm.  
The date is now stored and the Day Indicator will be displayed  
under the current day of the week (e.g. 1 = Monday, 2 =  
Tuesday, etc.)  
d. Use the  
the green  
or  
buttons to set the correct time then press  
button to confirm. Each press of the buttons will  
change the time by one minute and holding them down will  
change the time slowly at first and get progressively quicker.  
AM  
Note: If this mode is entered accidentally then press the  
AUTO, MAN or OFF buttons to exit.  
STEP 3: Running the Built-in Heating Program  
The thermostat is now ready for operation. Press the AUTO button and the built-in heating program  
will start running. Note: The built-in heating program has been designed to provide normal comfort  
requirements, but if you want to customise the settings please see the next section ‘Programming  
the CM727’.  
9
 
‘Efficient Daily Use’  
PROGRAMMING THE CM727  
The Built-in Heating Program  
The built-in heating program has 4 temperature level changes per day that can be set between  
3.00am and 2.50am the following day - allowing you to maintain the evening temperature after  
midnight. Each temperature level can be set between 5°C and 35°C, and adjusted in 0.5°C  
increments. The factory default program for heating is as follows.  
Monday to Friday  
Period  
1
2
3
4
(Day 1 to 5)  
Time  
6:30  
21°C  
8:00  
18°C  
18:00  
21°C  
22:30  
16°C  
Temperature  
Saturday & Sunday  
Period  
1
2
3
4
(Day 6 & 7)  
Time  
8:00  
21°C  
10:00  
21°C  
18:00  
21°C  
23:00  
16°C  
Temperature  
Reviewing the Heating Program  
To review or edit the heating program use the PROGRAM  
or  
buttons to navigate between the  
4 individual programming periods for that day. Use the DATE/DAY button to step through each day of  
the week, so the complete 7 day heating program can be reviewed or edited.  
Modifying the Heating Program  
To change the heating program:  
1
2
3
4
5
6
7
a. Press either of the PROGRAM  
enter the programming mode. The time / temperature  
settings for period on Monday (Day 1) will be  
or  
buttons to  
1
flashing as shown. The active period is highlighted by  
a flashing square around the numbers at the bottom of  
the screen and the selected day is shown with the day  
indicator.  
1
2
3
4
b. To adjust the period start time use the  
or  
buttons, the ‘OK?’ indicator will be displayed to  
confirm the change. Holding the button down will change the time quickly.  
Note: If you are pressing the  
or  
buttons and the display flashes the next period, it  
means the next period will be pushed forward.  
c. Once the required time is reached press the green  
button to confirm.  
Note: If the original time setting did not require adjustment press the green  
to step ‘d’.  
button to move  
d. The temperature setting for period  
1
on Monday (Day 1) will now be flashing. To adjust this  
button.  
press the or buttons and confirm the setting again by pressing the green  
e. The next time and temperature period will now be active. Adjust this by repeating steps b - d  
above until all 4 periods are set for Monday or press the AUTO button to run the program as  
set, at any time.  
You now have a choice of how to set the program for the next day:  
10  
 
PROGRAMMING THE CM727  
‘Efficient Daily Use’  
f. i) Press the COPY DAY button to copy Monday’s program into Tuesday. The display will go blank  
apart from the ‘non flashing’ day indicator, which indicates the day copied and the ‘flashing’ target  
day to copy the program to. To accept this day press the green  
target day press the DATE/DAY button until the ‘flashing’ day indicator is under the required  
day, then accept it by pressing the green button. Note: Once the target day is confirmed it  
button. To select a different  
becomes the day that is copied if the COPY DAY button is pressed again.  
OR  
ii) Press the DATE/DAY button to move the day indicator to Tuesday (Day 2). The program for that  
day can then be adjusted by following steps b to e. Programs for the remaining days can be set in  
the same way, using the DATE/DAY button to move to the next day.  
To exit the programming mode select the desired operating mode by pressing the AUTO, MAN or  
OFF buttons. Note: To run the adjusted program select the AUTO mode.  
Disabling / Enabling Time Periods  
The thermostat has 4 periods each day that can be programmed, but you may not need all of these  
switch points for your heating requirements. Therefore, any period from 2 to 4 can be removed from  
(or returned to) the heating program profile.  
To disable or enable time periods:  
a. To disable unwanted periods go to the desired period ( 2 to 4 ) using the PROGRAM  
or  
buttons to navigate, ensure the correct period is highlighted with the flashing square symbol.  
Press and hold the button for at least 2 seconds and the display will indicate the period has  
been removed from the program.  
b. To enable periods again follow the same procedure as above, navigating to the already disabled  
period. To enable this period again press and hold the button for at least 2 seconds.  
OPERATING THE CM727  
‘Using the Features’  
Choosing the Operating Mode  
The thermostat can operate in three different modes: Automatic, Manual or Off. To set the operating  
mode press either of the AUTO, MAN or OFF buttons. The screen indicates which mode is  
currently active by displaying AUTO, MAN or OFF.  
AUTO (automatic) mode sets the thermostat to follow the built-in temperature program (default  
or personalised). Operating the thermostat in this mode is the best way to maintain a high level  
of temperature comfort whilst maximising your energy savings.  
MAN (manual) mode sets the thermostat to act as a simple thermostat with a fixed setpoint  
throughout the day. The setpoint can be adjusted from 5°C to 35°C by using the  
or  
buttons. The thermostat will continue to maintain this temperature until another operating mode  
or temperature is selected.  
OFF mode sets the thermostat to control to a minimum temperature setting of 5°C (default) that  
acts as a frost protection measure for your home.  
11  
 
‘Using the Features’  
OPERATING THE CM727  
During Normal Operation  
Temperature Enquiry  
In AUTO, MAN and OFF operating modes the thermostat will display the current room  
temperature. To review the programmed ‘target’ temperature (the temperature which the  
thermostat is trying to maintain) press the  
button. This ‘target’ temperature value will be  
displayed flashing for 5 seconds before returning to the current room temperature value.  
Temperature Override  
During normal operation (AUTO mode) the programmed temperature can be adjusted manually  
by pressing the  
flash for 5 seconds - during this time the  
Note: This temperature override is cancelled at the next programmed temperature change.  
or buttons or the button. The ‘target’ temperature will be displayed and  
or buttons can be used to modify the set value.  
Adjusting the Time  
To adjust only the time during normal operation use the  
or  
buttons to adjust the time and  
press the green  
button again to confirm any changes.  
Using the Special Functions  
HOLIDAY Function  
The holiday function allows you to set a constant temperature (default = 10°C) for a specified  
number of days (from 1 - 99 days). This lets you save energy and related costs when you are  
away from home, but resumes normal operation on the day of your return.  
To set the Holiday function:  
a. Ensure the thermostat is running in AUTO or MAN operating modes.  
b. Press the holiday  
along with the holiday indicator  
button to display the holiday days counter and temperature setting,  
.
c. Press the or time buttons to set the holiday time (1 - 99 days) and press the green  
button to confirm.  
d. Press the  
or  
buttons to set the holiday temperature (5°C - 35°C) and press the green  
button to confirm.  
The thermostat will now control to the new temperature for the set number of days that your home is  
vacant. At midnight the holiday counter will be reduced by one until the selected number of days have  
passed. The thermostat will then return to normal operation as set by the MAN or AUTO mode. To  
cancel the HOLIDAY function or to exit the function at any time press the  
button a second time.  
12  
 
PROGRAMMING THE CM727  
Using the Special Features  
‘Using the Features’  
SERVICE indicator (optional)  
Note: This option only works if activated by your installer.  
The 'SERVICE' indicator is displayed at set  
intervals as a reminder that your heating system  
requires a routine check. Please call your installer  
to arrange a maintenance visit.  
The ‘SERVICE’ indicator will remain on the display  
of the CM727 until it is either reset or disabled by  
your installer. The CM727 and heating system will  
continue to operate as normal.  
Automatic Summer/Winter Time Change  
The CM727 has a built-in Automatic Summer/Winter Time Change feature that will automatically  
adjust the clock forward or backward by one hour for ‘Daylight Saving Time’. This is carried out  
on the last Sunday of March and October each year.  
Optimum Start  
Optimum Start is a program which ensures that the optimum temperature conditions are  
achieved at the required times. This is an Energy Efficiency feature that adjusts the start time  
of your heating system depending upon how cold it is. For example, on cold days your heating  
system will be started earlier to ensure that your home is warm when you get up (at the target  
temperature) and on warmer days the heating system will be started later to save energy. So,  
if the Optimum Start Feature is used, then the time / temperature settings which are entered  
into the thermostat should be set to when you want to be warm by and not when you want the  
heating system to start.  
13  
 
FAQ’s  
BDR91 Relay Box Controls Layout  
How do I change the batteries on the  
thermostat when they run out?  
The relay box will normally be found mounted  
close to the boiler.  
The thermostat constantly monitors the battery  
power level, which typically lasts for about  
years before needing replaced. When the power  
is running low flashing symbol will be  
2
a
displayed on the screen. To change the batteries  
follow the steps in the above section (‘STEP 1:  
Installing the Batteries’ on page 3), replacing  
the used batteries with new ones in Step c.  
Note: While changing the batteries your program  
settings will be stored but you may need to adjust  
the time settings to be correct.  
Push button  
and relay  
status LED’s  
What does it mean when the BDR91  
relay box green LED is ON?  
How do I set one temperature for the  
whole day?  
The green LED indicates normal operation of  
the radio frequency system. When the green  
LED is ON the boiler is also ON. When the LED  
is OFF the boiler is OFF.  
To operate as a simple thermostat with one  
temperature throughout the day, select the  
manual operating mode by pressing the  
MAN button. Adjust the temperature by  
pressing the  
or  
buttons - this can be  
set anywhere from 5°C to 35°C in 0.5°C steps.  
The thermostat will continue to maintain this  
temperature until another operating mode is  
selected or the temperature is adjusted.  
When do I need to use the push  
button?  
You should use the push button to control your  
boiler only when the RF communication is lost  
(see the Troubleshooting Guide).  
This product and its associated documentation and packaging are protected by various  
intellectual property rights belonging to Honeywell Inc. and its subsidiaries and existing under  
the laws of the UK and other countries. These intellectual and property rights may include patent  
applications, registered designs, unregistered designs, registered trade marks, unregistered  
trade marks and copyrights.  
Honeywell reserves the right to modify this document, product and functionality without notice.  
This document replaces any previously issued instructions and is only applicable to the  
product(s) described.  
This product has been designed for applications as described within this document. For use  
outside of the scope as described herein, refer to Honeywell for guidance. Honeywell cannot be  
held responsible for misapplication of the product(s) described within this document.  
Manufactured for and on behalf of the Environmental and Combustion Controls Division of Honeywell  
Technologies Sàrl, ACS-ECC EMEA, Z.A. La Pièce 16, 1180 Rolle, Switzerland by its Authorised  
Representative Honeywell Inc.  
14  
 
TROUBLESHOOTING THE CM727  
Symptom  
Remedy  
Blank Display (Power Loss).  
Check batteries are installed by removing the battery  
cover.  
Check batteries have been installed in the correct  
orientation.  
Replace the batteries.  
Display shows flashing  
symbol.  
The batteries in the thermostat are low on power  
- Replace the batteries.  
Display shows  
symbol.  
A fault has occurred in your heating system. Remove  
and re-insert the batteries.  
If the  
symbol does not clear after a few minutes  
contact your installer.  
Display shows the word 'SERVICE'  
Your installer has set a scheduled maintenance alert  
period on your CM727 as a recommendation that your  
heating system should receive a routine inspection.  
Call your installer to arrange a maintenance visit.  
Note: The CM727 and heating system will continue to  
operate as normal.  
BDR91 red LED is constantly on  
or flashing  
RF communication lost due to the wrong location of  
the room unit - Hook the room unit back on the wall  
bracket where RF communication was reliable.  
Call installer  
NOTE: You can control the boiler manually when the  
RF communication is lost: Press the BDR91 push  
button to switch the boiler on and off. When the green  
LED is on – the boiler is on.  
15  
 
WHAT IS A PROGRAMMABLE ROOM THERMOSTAT?  
...an explanation for householders  
A
programmable room thermostat is both  
a
programmer and  
a
room  
thermostat. A programmer allows you to set ‘On’ and ‘Off’ time periods to suit  
your own lifestyle. A room thermostat works by sensing the air temperature,  
switching on the heating when the air temperature falls below the thermostat  
setting, and switching it off once this set temperature has been reached.  
So, a programmable room thermostat lets you choose what times you want the heating to be on, and  
what temperature it should reach while it is on. It will allow you to select different temperatures in your  
home at different times of the day (and days of the week) to meet your particular needs.  
Turning a programmable room thermostat to a higher setting will not make the room heat up any faster.  
How quickly the room heats up depends on the design of the heating system, for example, the size  
of boiler and radiators.  
Neither does the setting affect how quickly the room cools down. Turning a programmable room thermostat  
to a lower setting will result in the room being controlled at a lower temperature, and saves energy.  
The way to set and use your programmable room thermostat is to find the lowest temperature settings  
that you are comfortable with at the different times you have chosen, and then leave it alone to do its job.  
The best way to do this is to set low temperatures first, say 18°C, and then turn them up by one degree  
each day until you are comfortable with the temperatures. You won’t have to adjust the thermostat  
further. Any adjustments above these settings will waste energy and cost you more money.  
If your heating system is a boiler with radiators, there will usually be only one programmable room  
thermostat to control the whole house. But you can have different temperatures in individual rooms  
by installing thermostatic radiator valves (TRVs) on individual radiators. If you don’t have TRVs, you  
should choose a temperature that is reasonable for the whole house. If you do have TRVs, you can  
choose a slightly higher setting to make sure that even the coldest room is comfortable, then prevent  
any overheating in other rooms by adjusting the TRVs.  
The time on the programmer must be correct. Some types have to be adjusted in spring and autumn  
at the changes between Greenwich Mean Time and British Summer Time.  
You may be able to temporarily adjust the heating programme, for example, ‘Override’, ‘Advance’ or  
‘Boost’. These are explained in the manufacturer’s instructions.  
Programmable room thermostats need a free flow of air to sense the temperature, so they must not be  
covered by curtains or blocked by furniture. Nearby electric fires, televisions, wall or table lamps may  
prevent the thermostat from working properly.  
Honeywell Control Systems Ltd.  
Arlington Business Park,  
Bracknell  
Berkshire  
RG12 1EB  
Technical Help Desk: 08457 678999  
50039991-003 A  
© 2009 Honeywell International Inc.  
 

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