Trane Tracer AH540 Setup And Operation page 108

Chapter 7 Troubleshooting
Table 69. DX cooling binary outputs do not energize
Probable cause
Normal operation
Manual output test
Fan mode Off
Diagnostic present
No power to the controller
Unit configuration
Unit wiring
98
The controller energizes the DX cooling binary output during cooling modes of opera-
tion. If low evaporator refrigerant temperature or coil defrost status binary input can
disable DX compressor operation until the condition is removed. DX cooling is also
suspended if the outdoor air temperature is less than the compressor lockout set-
point. Mechanical cooling lockout can also be enforced through the building automa-
tion system.
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 cooling outputs could be Off. See the "Performing a manual
output test" on page 84 for more information.
When a local fan mode switch (provided on the Trane zone sensor) determines the fan
operation, the Off position controls the unit Off and turns Off all outputs.
Specific diagnostics affect DX cooling operation. For more information, see Table 63
on page 91.
If the controller does not have power, a binary output remains de-energized. For the
controller or outputs to operate normally, it must have an input voltage of 24 Vac.
When the green Status LED is Off continuously, the controller does not have sufficient
power or has failed.
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,
DX cooling outputs may not work correctly. See Table 34 on page 75 and Table 39 on
page 77 for more information.
The wiring between the controller outputs and the compressor contactors must be
present and correct for normal DX cooling operation.
Explanation
CNT-SVX05B-EN