Trane Tracer AH540 Setup And Operation page 104

Chapter 7 Troubleshooting
Table 65. Valves stay open
Probable cause
Normal operation
Manual output test
Freeze avoidance
Diagnostic present
No power to the
controller
No power to the valves
Unit configuration
Unit wiring
94
The controller opens and closes the valves to meet the unit capacity requirements.
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 "Performing a manual output test"
on page 84.
When the controller is in the unoccupied mode with no demand for capacity (0%) and
the outdoor air temperature is below the freeze avoidance setpoint, the controller
opens the water valves (100%) and the face and bypass damper to prevent coil freez-
ing.
Specific diagnostics affect valve operation. For more information, see Table 63 on
page 91.
If the controller does not have power, a normally open valve remains open. For the
controller or valve to operate normally, it must have an input voltage of 24 Vac. When
the green LED is Off continuously, the controller does not have sufficient power or
has failed.
If the valve does not have power, a normally open valve remains open. The valves are
powered separately from the controller's output signal. If the valves do not have 24
Vac, the controller cannot operate the valves.
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.
The wiring between the controller outputs and the valve(s) must be present and cor-
rect for normal valve operation.
Explanation
CNT-SVX05B-EN