Diagnostics and Troubleshooting
140 UNT-SVX07J-EN
Test Button
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 p. 138 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 the tables
below).
Table 77. Tracer® ZN010 and ZN510 controller diagnostics
Diagnostic Latching Fan Valves Electric Heat Damper
Auxiliary temperature failure No Enabled No action No action No action
Condensate overflow detection Yes Off Closed Off Closed
Entering water temperature No Enabled Enabled Enabled Enabled
Fan mode failure No Enabled Enabled Enabled Enabled
Invalid unit configuration failure Yes Disabled Disabled Disabled Disabled
Low temperature detection Yes Off Open Off Closed
Maintenance required Yes Enabled No action No action No action
Setpoint No Enabled No action No action No action
Zone temperature failure No Off Closed Off Closed
Notes:
1. Priority Level: Diagnostics are listed in order from highest to lowest priority. The controller senses and records each diagnostic independently of other
diagnostics. It is possible to have multiple diagnostics present simultaneously. The diagnostics affect unit operation according to priority level.
2. Latching: A latching diagnostic requires a manual reset of the controller; while a non-latching diagnostic automatically resets when the input is
present and valid.
3. Enabled: End device is allowed to run if there is a call for it to run.
4. Disabled: End device is not allowed to run even if there is a call for it to run.
5. No Action: The diagnostic has no affect on the end device.
Table 78. Tracer® ZN520 controller diagnostics
Diagnostic Fan Other Outputs
1
Condensate overflow Off Valves Closed, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Low temperature detection Off Valves Open, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Low air flow - fan failure Off Valves Closed, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Space temperature failure Off Valves Closed, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Entering water temp failure On Valves Enabled
1
, Fresh air damper Enabled
2
, Electric heat Enabled
2
, Baseboard heat Off
Discharge air temp low limit Off Valves Open, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Discharge air temp failure Off Valves Closed, Fresh air damper Closed, Electric heat Off, Baseboard heat Off
Fresh air temp failure On Valves Enabled, Fresh air damper Minimum position
3
, Electric heat Enabled, Baseboard heat Enabled
Relative humidity failure On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
Generic 4–20mA failure On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
CO
2
Input failure On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
Maintenance required On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
Local fan mode failure On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
Local setpoint failure On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled, Baseboard heat Enabled
Invalid unit configuration Off Valves Disabled, Fresh air damper Disabled, Electric heat Disabled, Baseboard heat Disabled
Normal—power up On Valves Enabled, Fresh air damper Enabled, Electric heat Enabled
Notes:
1
The generic binary output (TB4-1, TB4-2) state is unaffected by all unit diagnostics.
2
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.
3
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.
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