t
rouBleShootIng
n
t
etWork
rouBleShootIng
Communication is achieved by taking the difference between
a positive dc signal and a negative dc signal. The positive dc
signal is termed "data 1" or "1'. Data 1 is positive with respect
to ground (or common). The negative dc signal is termed
"data 2" or "2". Data 2 is negative with respect to ground (or
common).
Data 1 should be approximately 2.8 volts dc. Data 2 should
be approximately 2.2 volts dc. The voltage difference between
data 1 and data 2 should be approximately 0.6 volts dc.
Verify that the bus DS1 dip switches are in the ON position.
1
2
LED COLOR
LED Status
Red Communications LED
(H1P)
1 Steady Flash
Green Receive LED (H2P)
Rapid Flashing
OFF ON
TERM
Indication
Off
Nominal condition
1 Flash
Communications Failure
2 Flash
Out-of-box reset
No power
Off
Communications error
No network found
Nominal network traffic
On Solid
Data 1/Data 2 miss-wire
The ComfortNet™ system is a fully communicating system,
constituting a network. Occasionally the need to troubleshoot
the network may arise. The integrated control module has
some onboard tools that can be used to troubleshoot the
network. These tools are: red communications LED, green
receive (Rx) LED, and the 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 5 seconds to reset the network.
dipswitch default factory Settings
Switch #
Setting
1
od dS1
2
1
od dS2
2
*OD DS2 switch 1 and 2 both must be turned off during normal
operation mode
Probable Causes
• None
• Unknown packet is received
• Control power up
• Learn button depressed
• No power to Outdoor unit
• Open fuse
• Communication error
• Broken/ disconnected communication
wire(s)
• AC is installed as a legacy/ traditional
system
• Control is "talking" on network as expected
• Data 1 and data 2 wires reversed at indoor
unit, thermostat, or outdoor unit
• Short between data 1 and data 2 wires
• Short between data 1 or data 2 wires
40
40
Purpose
ON
CT Communication Enabled
ON
CT Communication Enabled
Cooling Emergency Mode for
OFF
Future Use*
Cooling Emergency Mode for
OFF
Future Use*
Corrective Actions
• None
• Depress learn button
• None
• Check circuit breakers and fuses; Replace if needed
• Reset network by depressing learn button
• Check communication wires (data 1/ data 2 wires);
Replace if needed
• Check communication wires (data 1/ data 2 wires);
Replace if needed
• Check installation type (legacy/ traditional or com-
municating)
• Check data 1/ data 2 voltages
• None
• Check communication wires (data 1/ data 2 wires);
Replace if needed
• Check data 1/ data 2 voltages