Trane VUV Installation, Operation And Maintenance Manual page 106

Diagnostics and Troubleshooting
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 "Manual Output Test," p. 104
information about the manual output test.
Table 52. Tracer® ZN520 controller diagnostics
Diagnostic
Condensate overflow
Low temperature detection
Low air flow - fan failure
Space temperature failure
Entering water temp failure
Discharge air temp low limit
Discharge air temp failure
Fresh air temp failure
Relative humidity failure
Generic 4–20mA failure
CO Input failure
2
Maintenance required
Local fan mode failure
Local setpoint failure
Invalid unit configuration
Normal—power up
(a) The generic binary output (TB4-1, TB4-2) state is unaffected by all unit diagnostics.
(b) When the entering water temperature is required but not present, the Tracer® ZN520 controller generates a diagnostic to indicate the sensor loss condition. The controller
automatically clears the diagnostic once a valid entering water temperature value is present (non-latching diagnostic). When the entering water temperature sensor fails, the
controller prohibits all hydronic cooling operation, but allows the delivery of heat when heating is required. In the Cool mode, all cooling is locked-out, but normal fan and
outdoor air damper operation is permitted.
(c) When the outdoor air temperature sensor has failed or is not present, the Tracer® ZN520 controller generates a diagnostic to indicate the sensor loss condition. The controller
automatically clears the diagnostic once a valid outdoor air temperature value is present (non-latching diagnostic). When the outdoor air temperature sensor fails or is not
present, the controller prohibits economizer operation.
Building Automation System
Some building automation systems can reset diagnostics in
the Tracer® ZN520 controllers. For more complete
information, refer to the product literature for the building
automation system.
Diagnostic Reset for Tracer® ZN520
Controllers
Any device that can communicate the network variable
nviRequest (enumeration "clear_alarm") can reset diagnostics
in the Tracer® ZN520 controller. The controller also attempts
to reset diagnostics whenever power is cycled.
Cycling the Fan Switch for Tracer® ZN520
Controller
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).
106
for more
Fan
Off Valves Closed, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Off Valves Open, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Off Valves Closed, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Off Valves Closed, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
(a)1
On Valves Enabled , Fresh air damper Enabled
Off Valves Open, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Off Valves Closed, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
On Valves Enabled, Fresh air damper Minimum position
On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
Off Valves Disabled, Fresh air damper Disabled, Electric heat Disabled, Baseboard heat Disabled
On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled
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
1
Other Outputs
(b)
, Electric heat Enabled(b), Baseboard heat Off
(c)3
, Electric heat Enabled, Baseboard heat Enabled
Trane Service Tools
Rover, Trane's service tool for the controller, can reset
diagnostics present in the controller. For complete information
about Rover, refer to:
EMTX-SVX01*-EN Installation, Operation, and Programming:
Rover™ Service Tool
Alarm Reset
Any device that can communicate alarm reset information can
reset diagnostics present in the controller.
Table 52, p. 106).
UV-SVX005G-EN