506566−01 09/10
Page 2
CAUTION
This is a 24VAC Class 2 thermostat. Do not install on
voltages higher than 30VAC.
Do not short (jumper) across terminals on the gas
valve or at the system control to test installation. This
will damage the thermostat and void the warranty.
Do not switch system to cool if the outdoor tempera-
ture is below 45°F (7°C). This can damage the cooling
system.
Terms and Acronyms
AC Control:
Communicating air conditioning control. AC
controls low and high stage compressor operation, fan motor
operation, and all safety monitors in the unit.
Air Handler Control (AHC):
Communicating control for air
handler units. AHC controls operation of blower and heat
strips, and monitors all safety features in the unit.
Baud Rate:
Maximum speed of BUS 40K baud.
Byte:
8 bits of information transmitted on the RSBus.
Configuration:
Setup of system to identify other communi-
cating devices. Configuration is also used in setup of a vari-
able−capacity furnace to properly set furnace parameters.
Controller Area Network Protocol:
Rules for networking,
for transmission and receipt of information between commu-
nicating systems.
Discharge Air Sensor (DAS):
(Optional) Communicating
discharge air sensor. Provides discharge air temperature to
RSBus and User Interface.
Firmware:
Software stored on a memory chip, instead of be-
ing part of a program.
HP Control (Defrost Control) (UC):
Communicating defrost
control. UC controls low− and high−stage compressor opera-
tion, defrost operation, fan motor and reversing valve, and
monitors all safety features in the unit.
icomfort
−Enabled:
Any device in the HVAC system that
communicates with the icomfort
thermostat via the RSBus.
Integrated Furnace Control (IFC):
Communicating control
for furnace. IFC controls ignition, CAI and blower, and moni-
tors all safety features in the unit.
Memory Fault Recall:
Method of checking for stored errors.
Non−Communicating:
Any device in the HVAC system that
is NOT icomfort
−enabled and is NOT discoverable," and
does not communicate with the thermostat via the RSBus.
Programming Tabs:
The tabs for installer setup and pro-
gramming are shown in figure 1. When initially powered up,
the program begins in the setup tab. After setup has been
used once, all tabs will appear when re−entering the installer
setup. (See figure 1 for tab usage).
HELP
Use equipment
tab to adjust de-
vices after setup
has been com-
plete.
Use diagnostics
tab while equip-
ment is running to
locate potential
system malfunc-
tions.
Use alerts tab to
view and clear
critical alerts.
Use tests tab to
check out equip-
ment perfor-
mance after
completing set-
up.
Use setup tab to
discover commu-
nicating devices
at initial setup or
after making re-
pairs/changes to
the system.
Use HELP tab
to step through
the on−board in-
formation about
using the in-
staller program-
ming tool.
setup
tests
equipment
alerts
diagnostics
EXIT
Figure 1. Installer programming tabs
RSBus:
Residential Serial Bus (sometimes referred to as
Bus"). The means for transmitting data within the communi-
cating system. Consists of 4−wires:
C
24V common.
i+
+ (positive) data information connection.
i−
− (negative) data information connection.
R
24V power.
Software:
Programming and applications for computer.
Subnet:
The part of the communication network that con-
tains devices needed to control one functional HVAC system.
Subnet Controller (SC):
Local device that controls the sys-
tem. The subnet controller is an integral part of the communi-
cating thermostat.
User Interface (UI):
The thermostat touchscreen.
