Trane LO manual Tracer ZN.010 and ZN.510, Valves Stay Open, Probable Cause, Explanation

Tracer® ZN.010

and ZN.510

Table 17. Valves Stay Open

Probable Cause	Explanation
Normal operation	The controller opens and closes the valves to meet the unit capacity require-
	ments.
Valve override	The controller can communicate a valve override request to affect the
	valve operation.
Manual output test	The controller includes a manual output test sequence that verifies analog and
	binary output operation and the associated wiring. However, based on the
	current step in the test sequence, the valves may be open. Refer to the “Manual
	Output Test” section on page 51.
Diagnostic present	A specific list of diagnostics affects valve operation. For more information, see
	the “Diagnostics” section on page 50.
Sampling logic	The controller includes entering water temperature sampling logic that automati
	cally invokes during 2-pipe or 4-pipe changeover to determine if the
	entering water temperature is correct for the unit operating mode. Refer to the
	“Entering Water Temperature Sampling” section on page 41.
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 device, the valves may not work correctly.
Unit wiring	The wiring between the controller outputs and the valve(s) must be present and
	correct for normal valve operation. Refer to the typical unit wiring diagrams in
	the Appendix of this manual.

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