The Honeywell CM927 is a ‘wireless’ 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. 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 CM927 Programmable Room Thermostat.
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.
The time on the programmer must be correct. Some types have to be adjusted in spring and autumn to 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, and wall or table lamps may prevent the thermostat from working properly.
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 property rights may include patent applications, registered designs, unregistered designs, registered trademarks, unregistered trademarks, 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 the 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.
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:
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:
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 CM927’.
The Built-in Heating Program
The built-in heating program has 6 temperature level changes per day that can be set between 3.00 am and 2.50 am 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:
Monday to Friday
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 |
Saturday & Sunday
Period | 1 | 2 | 3 | 4 | 5 | 6 |
Time | 8:00 | 10:00 | 12:00 | 14:00 | 18:00 | 23:00 |
Temperature | 21°C | 21°C | 21°C | 21°C | 21°C | 16°C |
Reviewing the Heating Program
To review or edit the heating program move the slider switch to the PROG position then use the
Modifying the Heating Program
To change the heating program:
The thermostat has 6 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 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,
To enable time periods:
Navigate to the disabled period by moving the slider switch to the PROG position, then using the
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
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.
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 that the thermostat is trying to maintain) press the
In OFF operating mode the thermostat again displays the current room temperature, as above, but when the
Temperature Override
During normal operation (AUTO mode) the programmed temperature can be adjusted manually by pressing the
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:
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
PARTY Function
The party function allows you to extend your heating program by a specified number of hours at a particular temperature before resuming with the normal temperature program. This is especially useful when you want to maintain or increase the temperature during a special occasion such as a party or when entertaining guests. This function can also be used to reduce the temperature when you leave the house for a short period (shopping, visiting friends, etc) thus saving energy and saving you money.
To set the Party function:
The unit will now control to the new temperature for the set number of hours and then return to normal operation as set by the slider switch position (AUTO or MAN position). To cancel the PARTY setting or to exit the function at any time press
DAY OFF FUNCTION
The day off function allows you to temporarily run Sunday’s heating program for as many days as you desire. This is useful when you have a day off during your normal week or will, unintentionally, be at home on a workday due to illness, etc.
To set the Day Off function:
The thermostat will now control the alternative heating program for a set number of days before resuming with the normal heating program. To cancel the DAY OFF mode or to exit the function at any time press the
Adjusting the Time
To adjust only the time during normal operation use the
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:
Symptom | Possible Cause | Remedy |
The thermostat has a blank LCD screen. | Batteries not installed. | Check to see if there are batteries in the battery compartment and if the paper tab has been removed. |
Incorrect battery orientation. | Check that the batteries have been installed in the correct orientation. | |
Exhausted batteries. | Replace with new batteries. | |
The thermostat shows a flashing | Batteries are exhausted and need replacing. | Replace with new batteries. |
The thermostat’s LCD display shows a | The heating is not required at this moment. | The heat demand is sent to the BDR91 as a value between 0-100%. The BDR91 will adjust the boiler on time to meet this requirement. That is why the heating will be off sometimes even if the |
The thermostat shows a flashing symbol | Fault in thermostat | Remove and re-insert the batteries in the thermostat. If the symbol |
Symptom | Possible Cause | Remedy |
The thermostat’s LCD display works but the heating does not switch on (BDR91 LEDs are off or green one is on). | No power to the heating system. | Check that there is the power to the heating system. |
The program does not call for heat. | Move the slider switch to MAN and press | |
Wrong electrical connection. | Call the electrical installer to check the boiler and BDR91 power supply as well as the connection between the boiler and the BDR91. | |
The red LED on the BDR91 is constantly on or flashing. | RF communication lost due to the wrong location of the thermostat. | Hook the thermostat back on the wall bracket or replace the thermostat on the table stand in the position where RF communication was reliable. |
RF communication fault. | 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. | |
Heating switches ON or OFF too slowly or quickly. | The thermostat not set correctly for your system. | Call Installer. |
Temperature swings between too hot and too cold. | The thermostat not set correctly for your system. | Call Installer. |
How do I change the batteries on the CM927 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
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 on 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.
I want to use the table stand instead of wall mounted bracket. Where can I position the room unit?
It is important to keep the room unit in a location where reliable RF communication was proven. Advise your installer where would you like to position the room unit and he will check if the RF communication is reliable in the selected location(s).
Important: The Room Unit measures the temperature of the room where it is located. It is important that the placement of the Room Unit within the room is away from; draughts, direct sunlight, and other heat sources. As this is a wireless device certain objects could interfere with the RF signal – Leave at least 30cm distance from any metal objects (including wall boxes) and at least 1 meter from any other electrical equipment eg. radio, TV, PC, etc.
How do I remove the thermostat from the table stand or wall bracket?
After programming is finished always replace the thermostat back on the wall holder or table stand.
BDR91 Relay Box Controls Layout
What does it mean when the BDR91 relay box green LED is ON?
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
Can I use my CM927 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 buttons together for 5 seconds in any of the product operating modes (AUTO, MAN or OFF). The text ‘COOLING’ will be displayed for a moment 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:
Monday to Friday
period | 1 | 2 | 3 | 4 | 5 | 6 |
Time | 6:30 | 8:00 | 12:00 | 14:00 | 18:00 | 22:30 |
Temperature | 24°C | 28°C | 24°C | 28°C | 24°C | 24°C |
Saturday & Sunday
period | 1 | 2 | 3 | 4 | 5 | 6 |
Time | 8:00 | 10:00 | 12:00 | 14:00 | 18:00 | 23:00 |
Temperature | 24°C | 24°C | 24°C | 24°C | 24°C | 24°C |
How do I operate an HR 80 radiator controller with my CM927?
The setpoint is normally defined and controlled at the room thermostat. To override the local setpoint, turn the adjustment dial of the radiator controller unit until the desired set temperature (between 5 – 30 °C) is displayed. This local setpoint override remains valid until a time program from the room thermostat overwrites it automatically. In order to open or close the radiator valve completely turn the adjustment dial until “OFF” (closed) or “ON” (opened) is displayed. (If temperature limits are set, “ON”/”OFF” is not displayed – see installation manual 4.5.1). For more information please visit http://www.honeywelluk.com/download.aspx
Honeywell CM927 Programmable Room Thermostat User Guide
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