Instruction/ maintenance manual of the product CM921 Honeywell
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Honeywell Control Systems Ltd. Arlington Business Park, Bracknell Berkshire RG12 1EB T echnical Help Desk: 08457 678999 www .honeywelluk.com CM921 - User Guide 1 day Wireless Programmab le Room Thermostat with LoT technology 42011077-103 R1 © 2006 Honeywell International Inc.
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Contents GETTING ST ARTED 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 ................
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.
STEP 2: Setting the Date and Time T o set the Date and Time: a. Move the slider switch to the D A TE position. ‘SET THE DA Y’ 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 ‘DA Y OK?’ will be displayed.
The Built-in Heating Program The built-in heating pr ogram has 6 temperature level changes that can be set between 3.00am and 2.50am - allowing you to maintain the evening temperature after midnight.
b. T o adjust the period start time press the or buttons and ‘TIME 1 OK?’ will be displayed.
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 requir ements.
Choosing the Operating Mode The thermostat can operate in three different modes: Automatic, Manual or Off. T o set the operating mode move the slider switch to the desired position. The screen indicates which mode is currently active by displaying A UTO , MAN or OFF .
• T emperature Override During normal operation ( AUT O 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.
Changing the User P arameters The user mode allows you to modify some basic settings of the ther mostat to meet your personal preferences.
c. Now choose which one of the following parameters you would like to change: i) Change the time format ‘CLOCK SELECT’ should.
Symptom P ossible Cause Remedy The thermostat has a blank LCD screen. Batteries not installed. Check to see if there are batteries in the battery compartment and the paper tab has been removed. Incorrect battery orientation. Check that the batteries have been installed in the correctorientation.
Symptom P ossible Cause Remedy The thermostat’ s LCD display works but the heating does not switch on (HC60NG LEDs are off or green one is on). No power to heating system. Check that there is power to the heating system.
How do I change the batteries on the CM921 when they run out? The thermostat constantly monitors the battery power level, which typically last for about 2 years before needing replaced. When the power is running low a flashing symbol will be displayed on the screen.
How do I remove the thermostat fr om the table stand or wall brac ket? After pr ogramming is finished always replace the thermostat back on the wall holder or table stand.
Can I use my CM921 to contr ol my air -conditioning system? Y es, if your system has been set up correctly you can use your thermostat to control the cooling. T o switch the ther mostat between heating and cooling modes press the or buttons together for 5 seconds in any of the product operating modes ( A UT O , MAN or OFF ).
...an explanation f or householders (The following explanation applies to heating applications only) A programmable room thermostat is both a programmer and a room thermostat.
42011077-103 R1 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.
An important point after buying a device Honeywell CM921 (or even before the purchase) is to read its user manual. We should do this for several simple reasons:
If you have not bought Honeywell CM921 yet, this is a good time to familiarize yourself with the basic data on the product. First of all view first pages of the manual, you can find above. You should find there the most important technical data Honeywell CM921 - thus you can check whether the hardware meets your expectations. When delving into next pages of the user manual, Honeywell CM921 you will learn all the available features of the product, as well as information on its operation. The information that you get Honeywell CM921 will certainly help you make a decision on the purchase.
If you already are a holder of Honeywell CM921, but have not read the manual yet, you should do it for the reasons described above. You will learn then if you properly used the available features, and whether you have not made any mistakes, which can shorten the lifetime Honeywell CM921.
However, one of the most important roles played by the user manual is to help in solving problems with Honeywell CM921. Almost always you will find there Troubleshooting, which are the most frequently occurring failures and malfunctions of the device Honeywell CM921 along with tips on how to solve them. Even if you fail to solve the problem, the manual will show you a further procedure – contact to the customer service center or the nearest service center
