Trane Tracer ZN.520 Manual page 100

98
Troubleshooting
Table 63 Valves stay open
Probable cause Explanation
Unit wiring The wiring between the controller outputs and the valve(s) must
be present and correct for normal valve operation.
Unit configuration The controller must be properly configured based on the actual
installed end devices and application. When the unit configuration
does not match the actual end devices, the valves may not work
correctly.
Diagnostic present A specific list of diagnostic affects valve operation. For more
information, see Table on page 92.
Manual output test The controller includes a manual output test sequence you can use
to verify output operation and associated output wiring. However,
based on the current step in the test sequence, the valve(s) may be
open. Refer to "Manual output test" on page 88.
Sampling logic The controller includes entering water temperature sampling logic
which automatically invoked during 2-pipe and 4-pipe changeover
when the entering water temperature is either too cool or too hot
for the desired heating or cooling. Refer to "Entering water
temperature sampling function" on page 59.
Freeze avoidance When the fan is off with no demand for capacity (0%) and the
outdoor air temperature is below the freeze avoidance setpoint,
the controller opens the water valves (100%) to prevent coil
freezing. This includes unoccupied mode when there is no call for
capacity or any other time the fan is off.
Normal operation The controller opens and closes the valves to meet the unit
capacity requirements.
Table 64 DX or electric output(s) does not energize
Probable cause Explanation
Unit wiring The wiring between the controller outputs and the end devices
must be present and correct for normal operation.
Unit configuration The controller must be properly configured based on the actual
installed end devices and application. When the unit configuration
does not match the actual end devices, the unit may not work
correctly.
Diagnostic present A specific list of diagnostics affect compressor and electric heat
operation. For more information, see Table on page 92.
Manual output test The controller includes a manual output test sequence you can use
to verify output operation and associated output wiring. However,
based on the current step in the test sequence, the DX or electric
outputs may be off. Refer to "Manual output test" on page 88.
Freeze avoidance When the fan is off with no demand for capacity (0%) and the
outdoor air temperature is below the freeze avoidance setpoint,
the controller disables compressors and electric heat outputs. This
includes unoccupied mode when there is no call for capacity or
any other time the fan is off.
Normal operation The controller energizes the outputs only as needed to meet the
unit capacity requirements.
CNT-SVX04A-EN