The Honeywell CM900 Wireless (CM927 or CM921) is a modern wireless programmable room thermostat based on Honeywell’s proven programming philosophy. To further improve the ease of use, this product includes an extra large LCD display with backlighting and LoT Technology to assist customers during daily use.
The CM927/921 room thermostat communicates with the BDR91 Relay Box on an 868MHz Radio Frequency (RF) band to control a single heating system component such as a boiler, pump, or zone valve. Neither product will communicate with other RF products that use different frequencies or communication protocols.
Note: The RF link between the individual room thermostat (CM927/921) and Relay Box (BDR91) in system packs provided by Honeywell is pre-configured at the factory and therefore SHOULD be installed at the same site. This makes the installation process fast and easy, but if products from individual system packs are separated, or mixed with other pre-configured system packs during installations please refer to section 5.1 Binding / Rebinding Procedure to bind the desired units together and allow them to communicate with each other
As these products communicate using RF technology special care must be taken during installation. The location of the RF components as well as the building structure may influence the performance of the RF system. To assure system reliability, please review and apply the information given below. Within a typical residential building, the two products should communicate reliably within a 30m range. It is important to take into consideration that walls and ceilings will reduce the RF signal. The strength of the RF signal reaching the Relay Box depends on the number of walls and ceilings separating it from the room thermostat, as well as the building construction – the diagram below illustrates an example of typical signal strength reduction. Walls and ceilings reinforced with steel or plasterboard walls lined with metal foil reduce the RF signal significantly more. Once a position is selected for the room thermostat this can be checked using the RF Communication Test mode as described in section 2.2.3 Locating the Room Thermostat. If the position is unsuitable the Relay Box will not respond and an alternative position must be selected.
Installing the CM900 Wireless System
Please follow the illustrations and information below in sequence to install the Relay Box and room thermostat correctly. For applications other than gas boilers, enabling special features and to see what other system options are available refer to section 4) Installer Mode.
The Relay Box is an RF device. For the best performance install it in an open space. Leave at least 30cm distance from any metal objects including wall boxes and boiler housing. Do not mount on metal wall boxes. EMC compliance considerations Keep AC mains supply/load cables separate from signal wiring. Refer to Code of Practice standards EN61000-5-1 and -2 for guidance.
NOTE: The Relay Box contains no user-serviceable parts. It should be opened and installed by a qualified installer only.
WARNING: Electrostatic sensitive device! Do not touch the circuit board.
Burner (direct control)
NOTE: All wiring must be in accordance with IEE regulations
CAUTION: Observe ambient temperature and current limits (see the Relay Box wiring label)
Power Up
RF Communication Check (Test Mode)
To check the RF communication, hold the room thermostat about 2-3 meters from the installed Relay Box. Move the slider on the room thermostat to the OFF position then press the
NOTE: If the green LED is not switched at specified intervals, the red LED is flashing or if you are installing a replacement Relay Box or room thermostat, follow the procedures described in section 5.1 Binding / Rebinding Procedure.
Locating the Room Thermostat
While still in the Test Mode, as described in section 2.2.2, the room thermostat should be located taking the following into consideration and reviewing the illustrations below:
The room thermostat should be installed in an open space for best performance as it is a radio frequency device.
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.
Do not mount onto metal wall boxes. • It is recommended that the Relay Box is fully installed.
System Check
Now a simple test can be completed to check the full system has been installed correctly:
Automatic Operation
The Relay Box receives the heat demand (0-100%) signal from the room thermostat. The room thermostat will display the symbol on the LCD display whenever more heat is required. Depending on the demand the Relay Box will switch the heating device on to match the current requirements of the system.
The green LED indicates the status of the relay output:
Temporary Manual Override
Pressing the Relay Box button will override the current relay position. As soon as the next signal is received from the room thermostat the Relay Box will return back to automatic operation as the automatic control has higher priority than manual operation.
Communications Loss
If the RF communication is lost for a period of 1 hour the red LED will illuminate to indicate that no RF messages have been received during the last hour. The Relay Box will also enter the failsafe mode as selected in Installer Mode (see section 4.2 BDR91 Relay Box Fail-Safe Mode Setup). To allow manual control of the Relay Box output manual override is available in fail-safe mode. When RF communication is restored the Relay Box will automatically return to normal operation. You can now use the USER GUIDE supplied with the room thermostat to demonstrate how it works to the homeowner.
Basic Operation of the System
Installer Mode
Installer Mode is used to alter the system settings for specific applications, to use the special features of the room thermostat in a different way or to alter the factory preset parameters. Parameters are divided into two groups:
The failsafe mode defines the Relay Box output relay status if the RF communication is lost (e.g. when the room thermostat stops communicating due to discharged batteries). The factory setting keeps the relay permanently off when communications is lost. If this factory setting needs to be changed follow the instructions below:
Using the Room Thermostat for Specific Applications
The CM927/921 RF room thermostat is a versatile controller that can be used to control many different applications. For most typical applications, like wall-hung gas-fired combination boiler control or zone valve control, no adjustments from the factory settings are required. For other applications, like controlling an oil burner, the best system performance can be achieved by modifying selected parameters of the room thermostat in the Installer mode. The table below lists the most common settings used for specific applications.
Specific Application: | Setting: | What to change: | ||
Cycle/ Hour | Minimum ON Time | Note: All parameters listed below belong to category 2 – System Parameters (see Installer Parameters Table) | ||
HEATING | Gas Boiler (<30kW) | 6 | 1 | No changes required |
Oil Boiler | 3 | 4 | Set 1:Ot parameter to 4 Set 2:Cr parameter to 3 | |
Thermal Actuator | 12 | 1 | Set 2:Cr parameter to 12 | |
Zone Valve | 6 | 1 | No changes required | |
AIR- CONDITIONING | To enable switching between cooling and heating modes adjust parameter 4:HC in category 2 (0 = disabled, 1 = enabled). Now you can switch between these modes by pressing the | |||
Heat Pump / Air- Conditioner | 3 | 4 | Set 1:Ot parameter to 4 Set 2:Cr parameter to 3 | |
Fan Coil | 6 | 1 | No changes required |
Using the Special Features of the Room Thermostat
Special Feature: | Description: | Enable/Disable |
Optimisation (Variable Start Time) | The thermostat will adjust the start time in the morning/afternoon so the desired temperature is reached by the start of the program period. The system will restrict the start time to a max of 2 hours. | To enable: Set parameter 8: OP (category 1) to 1. |
Heating or Cooling Operation | This product can be used for heating or cooling applications. If you select cooling mode the control algorithm and factory default program will be modified. You can independently modify the heating and cooling profile. | To enable: Set parameter 4: HC (category 2) to 1. |
Summer/Winter Auto time change | This feature moves time automatically on the last Sunday of March and the last Sunday of October. The feature is factory enabled. | To enable: Set parameter 3: tC (category 1) to 1. |
Temperature Offset | If the thermostat is located in a particularly hot/cold location for reliable signal transmission reasons then the measured/displayed temperature can be adjusted by +/- 3°C. This is useful if the homeowner wants the reading to match another appliance temperature display. | Set parameter 12:tO (category 1) to the required offset value. |
Upper/Lower Temperature Limit | The normal upper temperature limit of 35°C can be reduced to 21°C to save the homeowner energy. The normal lower limit of 5°C can be increased up to 21°C to protect inhabitants from cold. | Set parameter 6:uL (category 1) to the desired upper limit. Set parameter 7:LL (category 1) to the desired lower limit. |
Installer Parameters Table
Category 1 – Room Thermostat Settings
Parameter | Parameter No. | Factory Default Setting | Optional Setting | ||
Category 1 Parameters – Room Thermostat Settings | |||||
Display | Description | Display | Description | ||
AM-PM / 24hr Display | 1:CL | 24 | 24 hr clock display format | 12 | 12 hr – AM/PM clock display format |
Reset Time/ Temp | 2:rP | 1 | Time / Temp profile set | 0 | Time / Temperature are as programmed |
Program | to factory default | ||||
Changes to 0 when | To restore the factory profile set to 1 | ||||
one of the time/temp | |||||
profiles are changed | |||||
Auto Summer/ Winter Time Change | 3:tC | 1 | Auto Summer/Winter Time Change Enabled | 0 | Auto Summer/Winter Time Change Disabled |
LCD Backlighting | 5:bL | 1 | Backlighting Enable | 0 | Backlighting Disabled |
Upper Temp Limit | 6:uL | 35 | 35°C Upper Temp. Limit | 21 to 34 | 21°C to 34°C adjustment in 1°C steps |
Lower Temp Limit | 7:LL | 5 | 5°C Lower Temp. Limit | 5 to 21 | 6°C to 21°C adjustment in 1°C steps |
Optimisation | 8:OP | 0 | Optimisation Disabled | 1 | Optimisation Enabled |
Temperature Offset | 12:tO | 0 | No temperature offset | -3 to +3 | -3°C to +3°C adjustment in 0.1°C steps |
Proportional Band Width | 13:Pb | 1.5 | Proportional band of 1.5 degrees | 1.6 to 3.0 | 1.6°C to 3.0°C adjustment in 0.1°C steps |
Reset Parameters | 19:FS | 1 | All settings at factory | 0 | Settings are as modified above |
to Factory Defaults | defaults | ||||
Changes to 0 when | To restore the factory profile set to 1 | ||||
one of the parameter | |||||
is changed |
Notes
Remember to always press the green
Category 2 – System Settings
Parameter | Parameter No. | Factory Default Setting | Optional Setting | ||
Category 2 Parameters – System Settings (press the button to access this category) | |||||
Display | Description | Display | Description | ||
Minimum boiler ON time | 1:Ot | 1 | 1 minute minimum ON time | 2 to 5 | Selection of 2, 3, 4 or 5 minutes minimum ON time |
Cycle Rate | 2:Cr | 6 | 6 cycles per hour (cph) | 3,9 or 12 | Selection of 3, 9 or 12 cph |
Heat/Cool Change | 4:HC | 0 | Disabled | 1 | Enabled |
Pump Exercise | 5:PE | 0 | Pump exercise disabled | 1 | Pump exercise enabled |
System Synchronisation | 6:Sn | 0 | Standard operation of the Room Unit | 1 | Room unit configured as Synchroniser |
Loss of Communications Instruction | 7:LC | 0 | Relay Off | 1 | Relay 20% on / 80% off |
The following Parameters are for the control of other Honeywell Wireless products such as Wireless Underfloor Heating controls and Wireless Radiator controls. For more information please contact Honeywell sales. | |||||
Room Temperature Sensor Use | 8:Su | 0 | BDR91 control | 1,2,3 or 4 | 1 – HR80/HM80 control with own/remote sensor (no temperature displayed) 2 – HR80/HM80/HCE80 control with CM sensor 3 – BDR91 control and HR80/HM80/ HCE80 control with own/remote sensor 4 – Hr80/HM80/HCE80 control with own/ remote sensor (temperature displayed) |
HR80 Window- Open Function | 9:HO | 0 | Disabled | 1 | Enabled |
HR80 Local Override | 10:HL | 1 | Enabled | 0 | Disabled |
Maximum Flow Setpoint | 11:uF | 55 | 55°C Maximum Flow Temp. | 0 to 99 | 0°C to 99°C adjustment in 1°C steps |
Minimum Flow Setpoint | 12:LF | 15 | 15°C Minimum Flow Temp. | 0 to 50 | 0°C to 50°C adjustment in 1°C steps |
Mixing Value Run Time | 13:Ar | 150 | 150 seconds | 0 to 240 | 0 to 240 sec. adjustment in 1sec steps |
Pump Overrun Run Time | 14:Pr | 15 | 15 minutes | 0 to 99 | 0 to 99 mins adjustment in 1min steps |
Binding / Rebinding Procedure
The binding operation described below is required if:
NOTE: During the binding procedure keep approximately 1m distance between the room thermostat and the Relay Box. To bind/rebind:
5.2 Multi-Zone System
Multiple room thermostats and Relay Box sets can also be used to control multi-zone systems and the CM927/921 room thermostat is compatible with a variety of other Honeywell products including HR80 radiator controllers (see below) and HCE80 underfloor heating controllers. If you intend to use it in this way additional installation and user instructions can be obtained by contacting the address at the end of this guide.
NOTE: Some of the labels supplied with the pack are for use in multi-zone applications.
Binding an HR80 Radiator Controller to the Room Thermostat
If several radiator controllers are to be controlled simultaneously in one room:
Trouble Shooting Guide
Symptom (Fault Message) | Possible Cause | Remedy |
The room thermostat displays | This is normal operation. The Relay Box cycles the relay on and off for times proportional to the demand signal (0-100%) from the room thermostat. The demand value is greater than 0%. | Using the |
The Relay Box does not react to setpoint changes on the room thermostat. | The room thermostat and Relay Box are not bound. | Reset the Relay Box by pressing and holding the push button for 15 seconds. Then follow the binding / rebinding procedure as described in section 5) Additional Installation Information. |
After the binding procedure the red LED is on and the green one is flashing once every 3 sec on the Relay Box. | Incorrect or incomplete binding procedure. Incorrect position of the room thermostat during binding. | Repeat the binding procedure. Repeat the binding procedure keeping approx. 1 m distance between the Relay Box and the room thermostat. |
The red LED on the Relay Box is illuminated (Communication loss) | The Relay Box receives no RF messages from the room thermostat: RF signal is blocked due to wrong location of the room thermostat.
Room thermostat batteries are exhausted. |
Re-locate the room thermostat following instructions in section 2) Installing the CM900 Wireless System. Replace batteries in the room thermostat. |
The CM927/921 room thermostat has a user-accessible mode that provides information useful to a remote service person and a means of checking whether the boiler is working. To access this move the slider switch to the OFF position then press and hold the button for 5 seconds. The room thermostat will enter the user settings mode. Next press and hold the
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 International Inc.
Honeywell Control Systems Ltd.
Arlington Business Park,
Bracknell, Berkshire
RG12 1EB
Technical Help Desk: 08457 678999
www.honeywelluk.com
Download Manual:
Honeywell CM900 Wireless Programmable Thermostat Installation Manual
Honeywell CM900 Wireless Programmable Thermostat Installation Manual
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