47
T
HERMOSTAT
M
ENU
If this furnace is installed with a
c
ommunicating compatible heat
pump, the system is recognized as a dual fuel system. The
balance point temperature should be set via the thermostat ad-
vanced menu. Navigate to the
THERMOSTAT
menu. Press the
INSTALLER CONFIG
key. Navigate to the
SETUP
menu and
press the
INSTALLER CONFIG
button.
D
IAGNOSTICS
Accessing the furnace’s diagnostics menu provides ready ac-
cess to the last six faults detected by the furnace. Faults are
stored most recent to least recent. Any consecutively repeated
fault is stored a maximum of three times. Example: A clogged
return air filter causes the furnace limit to trip repeatedly. The
control will only store this fault the first three
consecutive
times
the fault occurs. Navigate to the diagnostics menu as described
above in the thermostat installation manual.
NOTE:
It is highly recommended that the fault history be cleared
when performing maintenance or servicing the furnace.
N
ETWORK
TROUBLESHOOTING
Communications is achieved by taking the difference between
two dc signals. The signals and transmission lines are referred
to as “data 1” and “data 2”. Each transmission line is biased to
approximately 2.5Vdc. During data reception/transmission, the
data lines vary b5V and ground. (When data 1 is in-
creasing t5V, data 2 is decreasing towards ground and
when data 1 is decreasing towards ground, data 2 is increasing
t5V. Typically, the data 1 line is approximately 2.6Vdc
and the data 2 transmission line is approximately 2.3Vdc. The
voltage difference between data 1 and data 2 is typically 0.2 to
0.6 Vdc.
The ComfortNet™ system is a fully communicating system, and
thus, constitutes a network. Occasionally the need to trouble-
shoot the network may arise. The integrated furnace control has
some on-board tools that may be used to troubleshoot the net-
work. These tools are: red communications LED, green receive
(Rx) LED, and learn button.
•
Red communications LED – Indicates the status of the
network. The table below indicates the LED status and
the corresponding potential problem.
•
Green receive LED – Indicates network traffic. The table
below indicates the LED status and the corresponding
potential problem.
•
Learn button – Used to reset the network. Depress the
button for approximately 2 seconds to reset the network.