Honeywell CM921 User manual

Honeywell Control Systems Ltd.

Arlington Business Park,

Bracknell

Berkshire

RG12 1EB

Technical Help Desk: 08457 678999

www.honeywelluk.com

CM921 - User Guide

1 day Wireless Programmable Room Thermostat

with LoT technology

42011077-103 R1

Description

The Honeywell CM921 is a ‘wireless’ programmable room thermostat designed to

control you heating system efﬁciently, providing comfortable temperatures when you

are at home and energy savings when you are away. With ‘wireless’ communication

there is no need to provide a wired connection between the thermostat and boiler.

The following instructions explain how to set up, program and operate your

Honeywell CM921 Programmable Room Thermostat.

Features

Wireless connection to the boiler allows you to mount the Chronotherm in your

room without decor disruption

Armchair programming feature lets you program your Chronotherm while

resting comfortably in your armchair

Ergonomic User Interface features an ‘OK-button’ making the CM921 very

easy to use so you always stay in control.

LoT technology provides informative ‘on-screen’ feedback and operational

assistance to the user.

Extra Large LCD (Liquid Crystal Display) Screen with Backlight provides

added user friendliness and clearer viewing – even in the dark.

6 independent temperature levels per day lets you set any 6 temperatures you

require (from 5 to 35°C) so you can enjoy economical comfort every day

Holiday button saves energy by letting you reduce the temperature for 1 to 99

days while you are away from home, resuming normal operation on your return.

Automatic Summer/Winter Time Change will adjust the clock automatically for

‘Daylight Saving Time’.

Built-in Memory holds the user program indeﬁnitely so that it is never lost –

even if you remove the batteries.

Optimum Start option is an advanced feature which ensures that the optimum

temperature conditions are achieved at the required times (option set by your

installer).

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Contents

GETTING STARTED WITH THE CM921

STEP 1: Installing the Batteries......................................... 3

STEP 2: Setting the Date and Time................................... 4

STEP 3: Running the Built-In Heating Program ................ 4

PROGRAMMING THE CM921

The Built-in Heating Program............................................ 5

Reviewing the Heating Program ....................................... 5

Modifying the Heating Program........................................ 5

Disabling / Enabling Time Periods ................................... 7

OPERATING THE CM921

Choosing the Operating Mode ......................................... 8

AUTO mode............................................................. 8

MAN mode .............................................................. 8

OFF mode................................................................ 8

Adjusting the Time............................................................ 8

During Normal Operation.................................................. 8

Temperature Enquiry ............................................... 8

Temperature Override ............................................. 9

Using the Special Functions ............................................. 9

HOLIDAY Function .................................................. 9

FINE TUNING THE CM921

Changing the User Parameters ...................................... 10

Change the Time Format....................................... 11

Reset the Built-in Program..................................... 11

Summer / Winter Time Change ............................. 11

FAQ’s & TROUBLESHOOTING

Trouble Shooting Guide .................................................. 12

Frequently Asked Questions........................................... 14

WHAT IS A PROGRAMMABLE ROOM THERMOSTAT?

An explanation for householders .................................... 17

Controls Layout

Day / Date Display

Time Display

LoT technology Display

Heating On Indicator

Battery Low Indicator

Temperature Display

Temperature Change Buttons

Temperature Enquiry Button

Slider Switch

Green OK Button

Program Buttons

Battery Compartment Lid

Battery Compartment

Holiday Function Button

Time Change Buttons

1..6

AUTOMANOFF

CM921

DATE

PROG

AUTO

MAN

OFF

1 2 3 54 6

13 12 11

Manufactured for and on behalf of the Environment and Combustion Controls Division of Honeywell Technologies Sàrl, Ecublens, Route du Bois 37,

Switzerland by its Authorised Representative Honeywell International Inc.

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 screen displays some information

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. PLEASE RESPECT YOUR ENVIRONMENT!

Take care to dispose of used batteries carefully.

STEP 2: Setting the Date and Time

To set the Date and Time:

a. Move the slider switch to the DATE position. ‘SET THE DAY’ will be displayed on

the screen and the day digits will be ﬂashing.

b. Use the or buttons to set the correct day. When either of these buttons

are pressed ‘DAY OK?’ will be displayed. Once the correct day is reached, press

the green button to conﬁrm.

c. Now the month digits will start ﬂashing and ‘SET THE MONTH’ will be displayed.

Change the month and then the year using the or buttons, pressing the

green button to save any changes made. (If an invalid date has been entered

you will be returned to the start of the date setting mode).

d. After setting a valid date, the time digits will begin ﬂashing and ‘SET THE TIME’

will be displayed.

e. Use the or buttons to set the correct time. Each press of the button will

change the time by one minute and holding the button down will change the time

slowly at ﬁrst and get progressively quicker. Once the correct time is set, press

the green button to conﬁrm then ‘CHANGES SAVED’ will be displayed for a

moment followed by ‘DATE COMPLETE’.

Note: If the slider switch is moved at any time before ‘DATE COMPLETE’ is displayed

the changes to the date and time will NOT be saved.

STEP 3: Running the Built-in Heating Program

The thermostat is now ready for operation. Move the slider switch to the AUTO

position and the built-in heating program will start running. The built-in heating

program has been designed to provide normal comfort requirements, but if you want

to customise the default settings (as shown on the next page) please see the next

section ‘PROGRAMMING THE CM921’.



DATEPROGAUTOMANOFF

The Built-in Heating Program

The built-in heating program has 6 temperature level changes that can be set

between 3.00am and 2.50am - 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 move the slider switch to the PROG position

then use the or buttons to navigate between the 6 individual programming

periods.

Modifying the Heating Program

To change the heating program:

a. Set the slider switch to the PROG position, entering programming mode. ‘SET

TIME 1’ will be displayed and the time settings for period 1will be ﬂashing. The

active period is highlighted by a ﬂashing square symbol around the numbers at

the bottom of the screen.

Period 1 2 3 4 5 6

Time 6:30 8:00 12:00 14:00 18:00 22:30

Temperature 21°C 18°C 21°C 18°C 21°C 16°C

DATEPROGAUTOMANOFF

165432

b. To adjust the period start time press the or buttons and ‘TIME 1 OK?’ 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

change period, it means the next change will be pushed forward if you continue

to press or buttons).

c. Press the green button to conﬁrm the setting. ‘CHANGES SAVED’ is displayed

for 1.5 seconds then ‘SET TEMP 1’ will be shown.

Note: If the original time setting did not require adjustment press the green

button to move on to step ‘d.’.

d. The temperature setting for period 1will now be ﬂashing. To adjust this press the

or buttons and ‘TEMP 1 OK?’ will be displayed.

e. Press the green button to conﬁrm the setting. ‘CHANGES SAVED’ will be

displayed for a moment followed by ‘SET TIME 2’.

f. The next time and temperature period will now be active. Adjust this by repeating

steps b - e above until all 6 periods are set or move the slider switch to the AUTO

position to run the program as set, at any time.

g. After setting period 6‘CHANGES SAVED’ will be displayed as before.

i. To exit the programming mode move the slider switch to the desired operating

mode - AUTO, MAN or OFF. Note: To run the adjusted program select the AUTO

mode.

Note: If the unit is left in programming mode for more than 10 minutes without

the slider being moved or any buttons pressed, ‘MOVE THE SLIDER’ will be

displayed. Press a button to ﬁnish programming the thermostat or move the

slider to select the desired operating mode.

Disabling / Enabling Time Periods

The thermostat has 6 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 6

can be disabled or enabled as follows:

To disable time periods:

Go to the desired period ( 2to 6) by moving the slider switch to the PROG

position, then using the and buttons to navigate, ensuring 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.

To enable time periods:

Navigate to the disabled period by moving the slider switch to the PROG

position, then using the and buttons. Once selected ‘DISABLED’ will be

displayed. Press and hold the button for at least 2 seconds and ‘ENABLED’ will

be displayed for a moment before returning to normal programming mode.

Choosing the Operating Mode

The thermostat can operate in three different modes: Automatic, Manual or Off. To

set the operating mode move the slider switch to the desired position. The screen

indicates which mode is currently active by displaying AUTO, MAN or OFF.

• AUTO (automatic) mode

Automatic mode sets the thermostat to follow the 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

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

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. This value can be

adjusted by calling your installer.

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.

During Normal Operation

• Temperature Enquiry

In AUTO and MAN operating modes the thermostat will display the current room

temperature, which is indicated by the text ‘ROOM TEMP’ displayed on the

screen. 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 and the text ‘TARGET TEMP’ will be shown for 5

seconds before returning to the current room temperature value.

In OFF operating mode the thermostat again displays the current room

temperature, as above, but when the button is pressed the text ‘FROST TEMP’

is displayed indicating the set value to protect your home. To modify this value

please contact your installer.

• Temperature Override

During normal operation (AUTO mode) the programmed temperature can be

adjusted manually by pressing the or buttons. The ‘target‘ temperature

will be displayed and ﬂash 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.

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. Move the slider switch to the AUTO or MAN position.

b. Press the button to display the holiday days counter and temperature

setting, along with the holiday indicator .

The day after the current day will be selected and ‘RETURN DATE OK?’ will be

displayed. Press the or time buttons to set the holiday time (1 – 99 days).

Note: (The day and date will update according to the number of days

selected).

d. Press the green button to conﬁrm the setting.

e. ‘CHANGES SAVED’ will be displayed for a moment followed by ‘TEMP OK?’.

Press the or buttons to set the holiday temperature (5°C - 35°C)

f. Press the green button to conﬁrm the setting. ‘HOLIDAY MODE’ will now

be displayed on the screen until the return date is reached or the holiday

mode is cancelled.

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 slider switch position (AUTO or MAN position). To cancel the

HOLIDAY setting or to exit the function at any time press the button a second time

or move the slider switch to a different position.

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