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Troubleshooting
Resetting diagnostics
A reset clears any latching diagnostics and allows the controller to try to run the
air handling unit normally. If the latching condition is still present, the controller
immediately shuts down the air handling unit. A reset will restart a unit that is
running normally. A reset is similar to cycling power to the unit.
There are many ways to reset unit diagnostics:
• Manual output test at the controller
• Cycling power to the controller
• Building automation system
• Rover™ service tool
• Any communicating device able to access the controller's diagnostic reset
input
• Zone sensor fan mode switch
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. Refer to the
Manual output test section.
Cycling power
When the controller's 24VAC power is turned off, then on, 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 the
previous Diagnostics table).
Building automation system
Some building automation systems can reset diagnostics in the 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 controller. For more complete
information, refer to the Rover product literature.
Diagnostic reset input
Any device that can communicate the network variable nviRequest (enumeration
"clear_alarm") can reset diagnostics in the controller.
Zone sensor fan mode switch
When the zone sensor fan mode switch is changed from off to auto, the controller
attempts to reset all diagnostics. If the zone sensor fan mode switch has been
disabled by configuration, then the zone sensor fan mode switch is ignored and
it cannot be used to reset diagnostics.
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