Data Line Voltage Troubleshooting And Bias Switches - Daikin ComfortNet DX16TC Series Service Instructions Manual
Condensing units, split system heat pumps with r-410a refrigerant blowers, coils, & accessories
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- Service instructions manual (93 pages) ,
- Service instructions manual (122 pages)
Table of Contents
SERVICING
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing. Multiple power sources
may be present. Failure to do so may
cause property damage, personal injury
or death.
1. Turn on power to air handler or modular blower.
WARNING
Line Voltage now present.
0
2. Disconnect the 4-circuit harness connecting the control to
the electric heater kit.
3. Provide a thermostat demand for low stage auxiliary heat
(W1). Measure the voltage between circuits 1 and 3 at the
on-board electric heat connector. Voltage should measure
24VAC. Replace control if no voltage is present.
NOTE: Allow for any built-in time delays before making
voltage measurements. Any electric heater faults that are
present may prevent the heater output from energizing.
Verify that no heater faults are present before making
voltage measurements.
4. Provide a thermostat demand for high stage auxiliary heat
(W1 + W2). Measure the voltage between circuits 1 and
3 at the on-board electric heat connector. Measure the
voltage between circuits 2 and 3 at the on-board electric
heat connector. Voltage should measure 24VAC. Replace
control if no voltage is present.
Communications (Applies only to Systems with Compatible
ComfortNetTM Outdoor Unit and CTK0*Thermostat)
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. These are described below
a. Red communications LED – Indicates the status of the net-
work. Refer to the Network Troubleshooting Chart for the
LED status and the corresponding potential problem.
b. Green receive LED – Indicates network traffic. Refer to the
Network Troubleshooting Chart for the LED status and the
corresponding potential problem.
c. Learn button – Used to reset the network. Depress the
button for approximately 2 seconds to reset the network.
Voltages between the two data lines and between each data
line and common may be used to determine if the network is
operating properly.
Do the following to measure the voltages on the
communications data lines.
WARNING
Line Voltage now present.
Data Line Voltage Troubleshooting and Bias
Switches
Proper data voltage is essential to robust and reliable commu-
nication on the ComfortNet™ system. Any wiring issues must
be corrected for good communication.
• Poor wiring connections at the terminal blocks
• Low voltage wires that are shorted, grounded or broken.
• Communicating wires that are not connected to the proper
terminals at the connector.
• 24 volt common outside and inside are not at the same
ground potential
• Bias dip switch setting conflicts between indoor board and
outdoor board.
• It is STRONGLY recommended that you do not connect
multiple wires into a single terminal on the wiring
connector
• Wire nuts are recommended to connect multiple wires to
connector ensuring one wire is used for each terminal.
• Failure to do so may result in intermittent operation.
• Typical 18 AWG thermostat wire may be used to wire the
system components. One hundred feet is the maximum
length of wire between indoor and outdoor units or be-
tween indoor unit and thermostat.
• When outdoor transformer is used and there at least three
thermostat wires running to the outdoor unit use one
of the extra wires to connect the two 24 volt commons
together. This will ensure both 24 volt commons are at the
same ground potential.
• When outdoor transformer is used and there are only
two thermostat wires running to the outdoor unit ground
the 24 volt common "C" of the outdoor transformer to a
chassis ground (earth0 ground. This is not as good as the
third wire but it is better than leaving the outdoor 24 volt
common floating.
83
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Table of Contents
Troubleshooting
