Trane Zone Controller, N512 manual Valves remain open, DX or electric heat does not energize

	Troubleshooting
Table 19. Valves remain 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. Refer to applicable wiring diagram.
Failed end device	The valves must be checked to ensure proper operations.
Normal operation	The controller opens and closes the valves to meet the unit capacity requirements.
Manual output test	The controller includes a manual output test sequence you can use to verify output oper-
	ation and associated output wiring. However, based on the current step in the test
	sequence, the values may not be open. refer to the “Manual output test” on page 52.
Diagnostic present	Several diagnostics affect valve operation. For information about these diagnostics, see
	Table 16 on page 59.
Unit configuration	The controller must be properly configured based on the actual installed end devices and
	application. If the unit configuration does not match the actual end device, the valves may
	not work correctly.
Entering water	The controller includes entering water temperature sampling logic, which is automatically
temperature	initiated during 2-pipe and 4-pipe changeover if the entering water temperature is either
sampling logic	too cool or too hot for the desired heating or cooling. (See “AI1: Entering water tempera-
	ture” on page 17.)
Valve configuration	Make sure the valves are correctly configured, using the Rover service tool, as normally
	open or normally closed as dictated by the application.
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 pre-
	vent coil freezing. This includes unoccupied mode when there is no call for capacity or
	any other time the fan is off.
Table 20. DX or electric heat does not energize
Probable cause	Explanation
Unit wiring	The wiring between the controller outputs and the end devices must be present and cor-
	rect for normal operation. Refer to applicable wiring diagram.
Failed end device	Check the control contactors or the electric heat element, including any auxiliary safety
	interlocks, to ensure proper operation.
No power to the	If the controller does not have power, heat outputs do not operate. For the Tracer ZN521
controller	controller to operate normally, you must apply an input voltage of 24 Vac. If the green
	LED is off continuously, the controller does not have sufficient power or has failed.
Diagnostic present	Several diagnostics affect DX and electric heat operation. For information about these
	diagnostics, see Table 16 on page 59.
Normal operation	The controller controls compressor or electric heat outputs as needed to meet the unit
	capacity requirements.
Unit	The controller must be properly configured based on the actual installed end devices and
configuration	application. If the unit configuration does not match the actual end device, DX or electric
	heat may not operate correctly.
Manual output test	The controller includes a manual output test sequence you can use to verify output oper-
	ation and associated output wiring. However, based on the current step in the test
	sequence, the DX or electric heat outputs may be off. Refer to the “Manual output test”
	on page 52.

CNT-SVX07C-EN 65