Honeywell CM921 User Manual

Honeywell CM921 User Guide

About Honeywell CM921 User Manual

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.

Honeywell CM921 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).

Honeywell CM921 Controls Layout

Honeywell CM921 Controls Layout

  1. Day / Date Display
  2. Time Display
  3. LoT technology 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 thw Honeywell CM921

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:

Honeywell CM921 Battery Installation

  • Lift up the front cover of the thermostat to reveal the battery cover and product controls.
  • Remove the battery cover by pressing down and sliding out.
  • Insert the 2 x AA LR6 Alkaline Batteries supplied with the thermostat, ensuring the correct orientation (see ‘Controls Layout’ on page 2).
  • After a short pause the thermostat will display information on the screen and is now ready for use.
  • Replace the battery cover by sliding it irmly back into the front of the thermostat.

STEP 2: Setting the Date and Time

To set the Date and Time:

  • Move the slider switch to the DATE position. ‘SET THE DAY’ will be displayed on the screen and the day digits will be lashing.
  • 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.
  • Now the month digits will start lashing 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).
  • After setting a valid date, the time digits will begin lashing and ‘SET THE TIME’ will be displayed.
  • 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 irst and get progressively quicker. Once the correct time is set, press the green button to conirm 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.

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Honeywell CM921 User Manual

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