Description

The Honeywell CM901 is a programmable room thermostat designed to control your heating 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 CM901 to provide the most home comfort at the least cost.
Features
Ergonomic User Interface features an ‘OK-button’ making the CM901 very easy to use so you always stay in control.
Dynamic Text Display 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 let you set any 6 temperatures you require (from 5 to 35°C) so you can enjoy economical comfort throughout the day.
The 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.
Outside Temperature Sensor (optional accessory) can be fitted to the
CM901 to display the temperature outside your home.
Remote Temperature Sensor (optional accessory) can be fitted to the CM901 to control the room temperature in another location, concealing the CM901.
The optimum Start option is an advanced feature that ensures that the optimum temperature conditions are achieved at the required times.

Honeywell CM901 Programmable Room - Layout
1.Day / Date Display
2. Time Display
3. Dynamic Text Display
4. Heating On Indicator
5. Battery Low Indicator
6. Temperature Display
7. Temperature Change Buttons
8. Temperature Enquiry Button
9. Slider Switch
10. Green OK Button
11. Program Buttons
12. Battery Compartment Lid
13. Battery Compartment
14. Holiday Function Button
15. Time Change Buttons

GETTING STARTED WITH THE CM901

Honeywell CM901 Programmable Room - Setting

This section shows you how to set up 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.

Honeywell CM901 Programmable Room - Setting2

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.

Honeywell CM901 Programmable Room - Setting3

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.

Honeywell CM901 Programmable Room - DATE

b. Use the Honeywell CM901 Programmable Room - buttionbuttons to set the correct day. When either of these buttons is pressed ‘DAY OK?’ will be displayed. Once the correct day is reached, press the greenHoneywell CM901 Programmable Room - ok 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 Honeywell CM901 Programmable Room - buttionbuttons, pressing the greenHoneywell CM901 Programmable Room - ok 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 Honeywell CM901 Programmable Room - buttionbuttons 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 greenHoneywell CM901 Programmable Room - ok 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 customize the default settings (as shown on the next page) please see the next section ‘PROGRAMMING THE CM901’.

PROGRAMMING THE CM901

The Built-in Heating Program
The built-in heating program has 6 temperature level changes that can be set between 3.00 am and 2.50 am – 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:

Period123456
Time6:308:0012:0014:0018:0022:30
Temperature21°C18°C21°C18°C21°C16°C

Reviewing the Heating Program
To review or edit the heating program move the slider switch to the PROG position then use theHoneywell CM901 Programmable Room - 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 1 will be flashing. The active period is highlighted by a flashing square symbol around the numbers at the bottom of the screen.

Honeywell CM901 Programmable Room - PROG

b. To adjust the period start time press the Honeywell CM901 Programmable Room - buttionbuttons and ‘TIME 1 OK?’ will be displayed. Holding the button down will change the time quickly.
Note: If you are pressing the Honeywell CM901 Programmable Room - buttionbuttons and the display flashes the next change period, it means the next change will be pushed forward if you continue to press Honeywell CM901 Programmable Room - buttionbuttons).
c. Press the greenHoneywell CM901 Programmable Room - ok 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 greenHoneywell CM901 Programmable Room - ok button to move on to step ‘d.’.
d. The temperature setting for period 1 will now be flashing. To adjust this press the Honeywell CM901 Programmable Room - tempraturebuttons and ‘TEMP 1 OK?’ will be displayed.
e. Press the greenHoneywell CM901 Programmable Room - ok 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 asset, 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 – AUTOMAN, 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 ( 2 to 6 ) by moving the slider switch to the PROG position, then using the andHoneywell CM901 Programmable Room - or buttons to navigate, ensuring the correct period is highlighted with the flashing square symbol. Press and hold thei 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 andHoneywell CM901 Programmable Room - or buttons. Once selected ‘DISABLED’ will be displayed. Press and hold the ibutton for at least 2 seconds and ‘ENABLED’ will be displayed for a moment before returning to normal programming mode.

OPERATING THE CM901

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 personalized). Operating the thermostat in this mode is the best way to maintain a high level of temperature comfort whilst maximizing 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 Honeywell CM901 Programmable Room - tempraturebuttons. 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) which 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 Honeywell CM901 Programmable Room - buttionbuttons to adjust the time and press the greenHoneywell CM901 Programmable Room - ok 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 ibutton. 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 thei button has 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 Honeywell CM901 Programmable Room - temprature buttons. The ‘target‘ temperature will be displayed and flash for 5 seconds – during this time the Honeywell CM901 Programmable Room - temprature buttons can be used to modify the set value.
    Note: This temperature override is canceled 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 thebocxcxxxx button to display the holiday days counter and temperature setting, along with the holiday indicatorbocxcxxxx.
    c. The day after the current day will be selected and ‘RETURN DATE OK?’ will be displayed. Press theHoneywell CM901 Programmable Room - buttion 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 greenHoneywell CM901 Programmable Room - ok button to confirm the setting.
    e. ‘CHANGES SAVED’ will be displayed for a moment followed by ‘TEMP OK?’.
    Press the Honeywell CM901 Programmable Room - temprature  buttons to set the holiday temperature (5°C – 35°C)
    f. Press the green Honeywell CM901 Programmable Room - ok 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 canceled.

The thermostat will now control 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 bocxcxxxxbutton a second time or move the slider switch to a different position.

FINE-TUNING THE CM901

Changing the User Parameters
The user-mode allows you to modify some basic settings of the thermostat to meet your personal preferences. You can change the time display format (24hr or AM/PM), reset the heating program to the built-in settings, and disable or enable the summer/ winter time change feature.
To change any of these user’s parameters:
a. Move the slider switch to the OFF position, then press and hold the ibutton for approximately 5 seconds. button for approximately 5 seconds.

Honeywell CM901 Programmable Room - parameters

b. Once entered the following information will be shown on the screen:

Honeywell CM901 Programmable Room - parameters2

c. Now choose which one of the following parameters you would like to change:
i) Change the time format
‘CLOCK SELECT’ should be displayed on the screen – press the Honeywell CM901 Programmable Room - temprature buttons to select the preferred time format (12=AM/PM format, 24=24hr format) and the display will flash, indicating a change has been made. To confirm this change press the green Honeywell CM901 Programmable Room - okbutton.
ii) Reset the built-in program to the factory default
Press theHoneywell CM901 Programmable Room - llll time button once. The display will show ‘RESET PROGRAM’. Press theHoneywell CM901 Programmable Room - temprature button to select the preferred setting (0=user program, 1=factory program) and the display will flash, indicating a change has been made. To confirm this change press the green Honeywell CM901 Programmable Room - okbutton.
iii) Enable or disable summer/winter time change
Press Honeywell CM901 Programmable Room - llllthe time button twice. The display will show ‘AUTO CHANGE’. Press the Honeywell CM901 Programmable Room - temprature buttons to select the preferred setting (0=disabled/Off, 1=enabled/ On) and the display will flash, indicating a change has been made. To confirm this change press the greenHoneywell CM901 Programmable Room - ok button.
d. To exit the user mode move the slider switch to the AUTO, MAN, or OFF position.

FAQ’s & TROUBLESHOOTING

How do I change the batteries on the CM901 when they run out?
The thermostat constantly monitors the battery power level, which typically lasts for about 2 years before needing to be replaced. When the power is running low a flashing 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 and date settings to be correct.
How do I set one temperature for the whole day?
To operate as a simple thermostat with one temperature for a period of time, move the slider switch to the MAN position. Adjust the manual temperature by pressing the Honeywell CM901 Programmable Room - tempraturebuttons. 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.
What is Optimum Start?
Optimum Start is a program that 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 and not when you want the heating system to start.
Can I use my CM901 to control my air-conditioning system?
Yes, if your system has been set up correctly you can use your thermostat to control the cooling. To switch the thermostat between heating and cooling modes press the Honeywell CM901 Programmable Room - tempraturebuttons together for 5 seconds in any of the product operating modes (AUTO, MAN or OFF). The text ‘COOLING’ will be displayed for a moment on the screen to indicate the cooling operation is now active. The factory default program for cooling is specified in the table below, but this can be modified in the same way as the default heating program:

Period123456
Time6:308:0012:0014:0018:0022:30
Temperature24°C28°C24°C28°C24°C24°C

If something happens to my heating system how can I check that the thermostat is working?
Refer to the Troubleshooting Guide on page 15. If you still need assistance after this call your installer. The thermostat should only be opened or removed by a qualified professional to prevent possible injury from electric shock and/or damage to the product.
What other accessories can I buy that work with the CM901?

  1. Outside Temperature Sensor Accessory
    The Outside Temperature Sensor accessory can be fitted to your thermostat to display the outside temperature. By pressing the ibutton twice, the thermostat displays the external temperature.
  2. Remote Temperature Sensor Accessory
    The Remote Temperature Sensor accessory can be fitted to your thermostat to control the temperature of another room where it is inconvenient to locate the thermostat e.g. commercial premises where the public may tamper with the buttons.

Note: For more information on the above accessories please contact your installer.

Troubleshooting Guide

SymptomPossible CauseRemedy
CM901 has a blank LCD screenBatteries not installedCheck to see if there are batteries in the battery compartment and the paper tab has been removed
Incorrect battery orientationCheck that the batteries have been installed in the correct orientation
Exhausted batteriesReplace with new batteries
CM901 shows a flashing Honeywell CM901 Programmable Room - 111111111111 symbol on the LCD screenBatteries are exhausted and need replacingReplace with new batteries
The CM901’s LCD screen works but the heating does not switch onNo power to the heating systemCheck that there is the power to the heating system.
The program does not call for heatMove the slider switch to MAN and press Honeywell CM901 Programmable Room - dftggor increase the temperature a few degrees above the current room temperature. The heating should come on after a few seconds.
CM901 not connected to boiler properlyCall installer to check the electrical connection between the CM90 1 and the boiler.
Heating switches ON or OFF too slowly or quicklyCM901 is not set correctly for your systemCall Installer
Temperature swings between too hot and too cold.CM901 is not set correctly for your systemCall Installer
CM901 shows a flashing Honeywell CM901 Programmable Room - dal symbol on the LCD screenFault in CM901Remove and re-insert the batteries in the CM901. If the Honeywell CM901 Programmable Room - dal symbol does not clear itself in a few minutes call the installer

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 the 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.
WHAT IS A PROGRAMMABLE ROOM THERMOSTAT?
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 program, 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, walls, or table lamps may prevent the thermostat from working properly.

Honeywell CM901 Programmable Room - ce
Honeywell logo

Honeywell Control Systems Ltd.
Arlington Business Park,
Bracknell
Berkshire
RG12 1EB
Technical Help Desk: 08457 678999
www.honeywelluk.com
42010943-103 R1
© 2005 Honeywell International Inc.

Documents / Resources

Honeywell CM901 Programmable Room Thermostat [pdf] User Guide
CM901 Programmable Room Thermostat

References

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