Honeywell CM727 User manual

1
CM721..................................2-6
CM727................................7-11
USER GUIDE
This is a legacy product document
supported by Resideo. It is no
longer manufactured

2
Features
• Ergonomicuserinterfacefeaturingan‘OK-button’.
• LargeLCD(LiquidCrystalDisplay)Screen .
• 4independenttemperaturelevels(from5°Cto35°C).
• AutomaticSummer/WinterTimeChange.
• OptimumStarttoachievetherighttemperatureatthe
righttime.
• Built-inMemoryholdstheuserprogramindenitely.
Description
The Honeywell CM721 is a
programmable room thermostat
designed to control your heating
system efciently, 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.
Controls Layout
LCDScreen
BatteryLowIndicator
TimeDisplay
BurnerOnIndicator
TemperatureDisplay
1
2
3
611
12
13
7
8
9
10
4
5
BatteryCover
ProgramButtons
TimeChangeButtons
SetDateButton
TemperatureChangeButtons
TemperatureEnquiryButton
OperatingModeButtons
GreenOKButton
BatteryCompartment
1. . 4
AUTO
AU TO
MAN
OFF
13
1 2 43 5
7
8
9
6
11
12
10
PROGRAM
CM721
D AT E
14
14
CM721 - USER GUIDE

3
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 or buttons to set the current month of the
year (e.g. m 01 = January) then press the green button to
confirm.
c. Press the or buttons to set the current year (e.g. yr 06
= 2006) then press the green button to confirm.
The date is now stored.
d. Use the or buttons to set the correct time then press
the green 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.
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’.
AM

4
Period 1 2 3 4
Time 6:30 8:00 18:00 22:30
Temperature 21°C 18°C 21°C 16°C
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.
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  or  buttons to
enterthe programmingmode.Thetime/temperature
settingsforperiod 1  will beashing as shown. The
active period is highlighted by a ashing square
aroundthenumbersatthebottomofthescreen.
b. Toadjusttheperiodstarttimeusethe or buttons,thedisplaywillstopashing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conrm.
Note: If the original time setting did not require adjustment press the green button to move
to step ‘d’.
d. Thetemperaturesettingforperiod 1willnowbeashing.Toadjustthispressthe or
buttonsandconrmthesettingagainbypressingthegreen button.
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prole.
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ashing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.
4321
‘Efficient Daily Use’ PROGRAMMING THE CM721

5
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 xed 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.
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ashing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 or buttonsorthe button.The‘target’temperaturewillbedisplayedand
ashfor5seconds-duringthistimethe or buttonscanbeusedtomodifythesetvalue.
Note: This temperature override is cancelled at the next programmed temperature change.
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conrm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.
OPERATING THE CM721 ‘Using the Features’

6
How do I change the batteries on the
thermostat when they run out?
The thermostat constantly monitors the battery
power level, which typically lasts for about 2
yearsbeforeneedingreplaced.Whenthepower
is running low a ashing  symbol will be
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.
How do I set one temperature for the
whole day?
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.
FAQ’s
• 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.
‘Using the Features’ OPERATING THE CM721
BDR91 Relay Box Controls Layout
The relay box will normally be found mounted
close to the boiler.
What does it mean when the BDR91
relay box green LED is ON?
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.
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).
Push button
and relay
status LED’s

7
Symptom
BlankDisplay(PowerLoss).
Displayshowsashing
symbol.
Displayshows symbol.
Displayshowstheword'SERVICE'
BDR91redLEDisconstantlyon
orashing
Remedy
Checkbatteriesareinstalledbyremovingthebattery
cover.
Checkbatterieshavebeeninstalledinthecorrect
orientation.
Replacethebatteries.
Thebatteriesinthethermostatarelowonpower
-Replacethebatteries.
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.
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.
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.
TROUBLESHOOTING THE CM721

8
CM727 - USER GUIDE
Features
• 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.
• Built-inMemoryholdstheuserprogramindenitely.
Description
The Honeywell CM727 is a
programmable room thermostat
designed to control your heating
system efciently, 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.
Controls Layout
LCDScreen
BatteryLowIndicator
TimeDisplay
BurnerOnIndicator
DayIndicator
TemperatureDisplay
1
2
3
4
5
6
HolidayFunctionButton
ProgramButtons
CopyDayButton
SetDate/DayButton
TimeChangeButtons
TemperatureChangeButtons
TemperatureEnquiryButton
OperatingModeButtons
GreenOKButton
BatteryCompartment
BatteryCover
7
8
9
10
11
12
13
14
15
16
17
COPY
D AY
DATE/
D AY
1. . 4
AUTO
1234567
AU TO
MAN
OFF
16
15
17
1 2 43 5
8
9
10
7
12
13
14
11
6
PROGRAM
CM727

9
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 or buttons to set the current month of the
year (e.g. m 01 = January) then press the green button to
confirm.
c. Press the or buttons to set the current year (e.g. yr 06
= 2006) then press the green 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 or buttons to set the correct time then press
the green 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.
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’.
AM

10
‘Efficient Daily Use’ PROGRAMMING THE CM727
Modifying the Heating Program
To change the heating program:
a.
Press either of the PROGRAM  or  buttons to
enterthe programmingmode.Thetime/temperature
settings for period
1
 on Monday (Day 1) will be
ashingasshown.Theactiveperiodishighlightedby
aashingsquarearoundthenumbersatthebottomof
thescreenandtheselecteddayisshownwiththeday
indicator.
b. Toadjusttheperiodstarttimeusethe or buttons,the‘OK?’indicatorwillbedisplayedto
conrm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conrm.
Note: If the original time setting did not require adjustment press the green button to move
to step ‘d’.
d. Thetemperaturesettingforperiod 1onMonday(Day1)willnowbeashing.Toadjustthis
pressthe or buttonsandconrmthesettingagainbypressingthegreen button.
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:
1234567
4321
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.
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.
Period 1 2 3 4
Time 6:30 8:00 18:00 22:30
Temperature 21°C 18°C 21°C 16°C
Monday to Friday
(Day 1 to 5)
Period 1 2 3 4
Time 8:00 10:00 18:00 23:00
Temperature 21°C 21°C 21°C 16°C
Saturday & Sunday
(Day 6 & 7)

11
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ashing’dayindicator,whichindicatesthedaycopiedandthe‘ashing’target
daytocopytheprogramto.Toacceptthisdaypressthegreen button.Toselectadifferent
target day press the DATE/DAY button until the ‘ashing’ day indicator is under the required
day,thenacceptitbypressingthegreen button.Note: Once the target day is confirmed it
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prole.
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ashing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xed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.

12
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ashing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 or buttonsorthe button.The‘target’temperaturewillbedisplayedand
ashfor5seconds-duringthistimethe or buttonscanbeusedtomodifythesetvalue.
Note: This temperature override is cancelled at the next programmed temperature change.
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specied
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 buttontodisplay theholidaydayscounterand temperaturesetting,
alongwiththeholidayindicator .
c. Pressthe or timebuttonstosettheholidaytime(1-99days)andpressthegreen
buttontoconrm.
d. Pressthe or buttonstosettheholidaytemperature(5°C-35°C)andpressthegreen
buttontoconrm.
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.
‘Using the Features’ OPERATING THE CM727

13
Using the Special 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.
PROGRAMMING THE CM727 ‘Using the Features’

14
How do I change the batteries on the
thermostat when they run out?
The thermostat constantly monitors the battery
power level, which typically lasts for about 2
yearsbeforeneedingreplaced.Whenthepower
is running low a ashing  symbol will be
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.
How do I set one temperature for the
whole day?
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.
FAQ’s
BDR91 Relay Box Controls Layout
The relay box will normally be found mounted
close to the boiler.
What does it mean when the BDR91
relay box green LED is ON?
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.
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).
Push button
and relay
status LED’s
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.

15
Symptom
BlankDisplay(PowerLoss).
Displayshowsashing
symbol.
Displayshows symbol.
Displayshowstheword'SERVICE'
BDR91redLEDisconstantlyon
orashing
Remedy
Checkbatteriesareinstalledbyremovingthebattery
cover.
Checkbatterieshavebeeninstalledinthecorrect
orientation.
Replacethebatteries.
Thebatteriesinthethermostatarelowonpower
-Replacethebatteries.
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.
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.
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.
TROUBLESHOOTING THE CM727

16
50039991-003A
©2009HoneywellInternationalInc.
Honeywell Control Systems Ltd.
Arlington Business Park,
Bracknell
Berkshire
RG12 1EB
Technical Help Desk: 08457 678999
www.honeywelluk.com
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.
®