Trane LO - Manual (Page 81)

UNT-IOM-6 81
Tracer ® ZN.520
If a Low Temperature Detection diagnostic recurs within 24 hours after
an automatic diagnostic reset, you must manually reset the diagnos-
tic. See other possible methods for resetting diagnostics in this
section.
Manual output test: You can use the Test button on the controller
either during installation to verify proper end device operation or during
troubleshooting.When you press the Test button, the controller
exercises all outputs in a predefined sequence. The first and last
outputs of the sequence reset the controller diagnostics. See the
previous section for more information about the manual output test.
Cycling power: When someone turns off the controller’s 24 VAC
power, then re-applies power, the unit cycles through a power up
sequence.By default, the controller attempts to reset all diagnostics
at power up.Diagnostics present at power up and those that occur
after power up are handled according to the defined unit diagnostics
sequences (see previous Diagnostics table).
Building automation system: Some building automation systems can
reset diagnostics in the Tracer ® ZN.520 controller.For more complete
information, refer to the product literature for the building automation
system.
Rover™ service tool: Rover service tool can reset diagnostics in the
Tracer ® ZN.520 controller. For more complete information, refer to the
Rover™ Installation, Operation, and Programming manual.
Diagnostic reset: Any device that can communicate the network
variable nviRequest (enumeration “clear_alarm”) can reset diagnostics
in the Tracer ® ZN.520 controller.The controller also attempts to reset
diagnostics whenever power is cycled.
Cycling the fan switch: If the user cycles the fan speed switch from
off to any speed, the controller resets all diagnostics.Diagnostics
may recur immediately if the problem still exists.
The green LED normally indicates whether or not the controller is
powered on (24 VAC).