41
SERVICING
NETWORK TROUBLESHOOTING
The ComfortNet™ system is a fully communicating system,
and thus, constitutes a network. Occasionally the need to
troubleshoot the network may arise. The integrated air
handler control has some on-board tools that may be used to
troubleshoot the network. These tools are: red communications
LED, green receive (Rx) LED, and learn button. Refer to the
Communications Troubleshooting Chart and Air Handler
Diagnostic Codes below for error codes, possible causes and
corrective actions.
•
Red communications LED – Indicates the status of the
network. The table below indicates the LED status and the
corresponding potential problem.
•
Green receive communication 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.
LED
LED
Status
Indication
Possible Causes
Corrective Action(s)
Notes & Cautions
Red
Communications
LED
Off
•
Normal
condition
•
None
•
None
•
None
1 Flash
•
Communications
Failure
•
Communications Failure
•
Depress Learn Button
•
Verify that bus BIAS and TERM
dipswitches are in the ON
position.
•
Depress once quickly for
a power-up reset
•
Depress and hold for 2
seconds for an out-of-box
reset
2 Flashes
•
Out-of-box reset
•
Control power up
•
Learn button depressed
•
None
•
None
Green Receive
LED
Off
•
No power
•
Communications
error
•
No power to air handler
•
Open fuse
•
Communications error
•
Check fuses and circuit
breakers; replace/reset
•
Replace blown fuse
•
Check for shorts in low voltage
wiring in air handler/system
•
Reset network by depressing
learn button
•
Check data 1/ data 2 voltages
•
Turn power OFF prior to
repair
1 Steady
Flash
•
No network
found
•
Broken/ disconnected data wire(s)
•
Air handler is installed as a non-
communicating/ traditional system
•
Check communications wiring
(data 1/ data 2 wires)
•
Check wire connections at
terminal block
•
Verify air handler installation
type (non-communicating/
traditional or communicating)
•
Check data 1/ data 2 voltages
•
Turn power OFF prior to
repair
•
Verify wires at terminal
blocks are securely
twisted together prior to
inserting into terminal
block
•
Verify data1 and data
voltages as described
above
Rapid
Flashing
•
Normal network
traffic
•
Control is “talking” on network as
expected
•
None
•
None
On Solid
•
Data 1/ Data 2
miss-wire
•
Data 1 and data 2 wires reversed
at air handler, thermostat, or
ComfortNet™ compatible outdoor
AC/HP
•
Short between data 1 and data 2
wires
•
Short between data 1 or data 2
wires and R (24VAC) or C (24VAC
common)
•
Check communications wiring
(data 1/ data 2 wires)
•
Check wire connections at
terminal block
•
Check data 1/ data 2 voltages
•
Turn power OFF prior to
repair
•
Verify wires at terminal
blocks are securely
twisted together prior to
inserting into terminal
block
•
Verify data1 and data
voltages as described
above
COMMUNICATIONS TROUBLESHOOTING CHART
