CM900 Wireless
Installation Guide
CM927 / CM921 Wireless Programmable
Room Thermostat & BDR91 Relay Box
Description
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.
Table of Contents
Section Page
1) Installation Information ................................. 2
2) Installing the CM900 Wireless System......... 3
2.1 Installing the Relay Box................................... 3
2.2 Installing the Room Thermostat ........................ 4
2.2.1 Power Up............................................... 4
2.2.2 RF Communication Check ........................ 4
2.2.3 Locating the Room Thermostat ................. 5
2.3 System Check................................................ 5
3) Basic Operation of the System..................... 6
3.1 Automatic Operation....................................... 6
3.2 Temporary Manual Override............................. 6
3.3 Communication Loss ...................................... 6
4) Installer Mode................................................. 6
4.1 Entering Installer Mode ................................... 7
4.2 BDR91 Relay Box Fail-Safe Mode Setup............ 7
4.3 Using the Room Thermostat for Specific Applications
.. 8
4.4 Using the Special Features of the Room Thermostat
.. 8
4.5 Installer Parameters Table ............................... 9
4.5.1 Category 1 - Room Thermostat Settings ..... 9
4.5.2 Category 2 - System Settings.................. 10
5) Additional Installation Information............. 11
5.1 Binding / Rebinding Procedure ...................... 11
5.2 Multi-Zone System........................................ 11
5.3 Binding an HR80 Radiator Controller
to the Room Thermostat ................................ 11
6) Trouble Shooting.......................................... 12
6.1 Trouble Shooting Guide................................. 12
6.2 Diagnostics Mode ........................................ 12
50039987-003 A
