47
N
ORMAL
S
EQUENCE
OF
O
PERATION
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.
S
YSTEM
T
ROUBLESHOOTING
NOTE:
Refer to the instructions accompanying the CT compatible
outdoor AC/HP unit for troubleshooting information.
Refer to the Troubleshooting Chart in the Appendix for a listing of
possible furnace error codes, possible causes and corrective
actions.
N
ORMAL
S
EQUENCE
OF
O
PERATION
P
OWER
U
P
The normal power up sequence is as follows:
•
115 VAC power applied to furnace.
LED LED
Status
Indication
Possible Causes
Corrective Action(s)
Notes & Cautions
Off
x
Normal condition
x
None
x
None
x
None
1 Flash
x
Communications
Failure
x
Communications
Failure
x
Depress Learn Button
x
Verify that bus BIAS
and TERM
dipswitches are in the
ON position.
x
Depress once
quickly for a power-
up reset
x
Depress and hold
for 2 seconds for
an out-of-box reset
Red
Communications
LED
2 Flashes
x
Out-of-box reset
x
Control power up
x
Learn button
depressed
x
None
x
None
Off
x
No power
x
Communications
error
x
No power to furnace
x
Open fuse
x
Communications error
x
Check fuses and
circuit breakers;
replace/reset
x
Replace blown fuse
x
Check for shorts in
low voltage wiring in
furnace/system
x
Reset network by
depressing learn
button
x
Check data 1/ data 2
voltages
x
Turn power OFF
prior to repair
1 Steady
Flash
x
No network found
x
Broken/ disconnected
data wire(s)
x
Furnace is installed as
a legacy/ traditional
system
x
Check
communications
wiring (data 1/ data 2
wires)
x
Check wire
connections at
terminal block
x
Verify furnace
installation type
(legacy/ traditional or
communicating)
x
Check data 1/ data 2
voltages
x
Turn power OFF
prior to repair
x
Verify wires at
terminal blocks are
securely twisted
together prior to
inserting into
terminal block
x
Verify data1 and
data voltages as
described above
Rapid
Flashing
x
Normal network
traffic
x
Control is “talking” on
network as expected
x
None
x
None
Green Receive
LED
On Solid
x
Data 1/ Data 2
miss-wire
x
Data 1 and data 2
wires reversed at
furnace, thermostat,
or CT™ compatible
outdoor AC/HP
x
Short between data 1
and data 2 wires
x
Short between data 1
or data 2 wires and R
(24VAC) or C (24VAC
common)
x
Check
communications
wiring (data 1/ data 2
wires)
x
Check wire
connections at
terminal block
x
Check data 1/ data 2
voltages
x
Turn power OFF
prior to repair
x
Verify wires at
terminal blocks are
securely twisted
together prior to
inserting into
terminal block
x
Verify data1 and
data voltages as
described above
