Basic Operation Of The System; Automatic Operation; Temporary Manual Override; Communication Loss - Honeywell CM900 Installation Manual

3) Basic Operation of the System

3.1 Automatic Operation

The receiver box receives the heat demand (0-
100%) signal from the room thermostat. The
room thermostat will display the
LCD display whenever more heat is required.
Depending on the demand the receiver 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:
• Green LED on = relay on
• Green LED off = relay off

3.2 Temporary Manual Override

Pressing the receiver box button will override the current relay position. As soon as the next signal is
received from the room thermostat the receiver 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 receiver box will also enter the failsafe mode as selected in Installer Mode (see section 4.2 HC60
Receiver Box Fail-Safe Mode Setup). To allow manual control of the receiver box output manual override
is available in fail-safe mode. When RF communication is restored the receiver 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.

4) 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:
- Category 1 parameters – Room Thermostat Setup
- Category 2 parameters – System Setup.
These are all listed in section 4.5 Installer Parameters Table.

symbol on the
CM900 Wireless - Programmable Room Thermostat
HC60NG Receiver Box
Push button and
relay status LED's