6 CM900 Wireless - Programmable Room Thermostat
3.1 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:
• GreenLEDon=relayon
• GreenLEDoff=relayoff
3.2 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.
3.3 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
home owner.
3) Basic Operation of the System4) Installer ModeInstaller 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:
- Category 1 parameters – Room Thermostat Setup
- Category 2 parameters – System Setup.
These are all listed in section 4.5 Installer Parameters Table.
BDR91 Relay Box
Push button and
relay status LED’s