ZN010, ZN510, and ZN520 Controllers
UNT-SVX07E-EN
139
•
By cycling power to the controller
•
By using a building automation system
•
By using the Rover service tool
•
By using any other communicating device able to
access the controller’s diagnostic reset input (Tracer
ZN510 or ZN520 only)
•
By cycling the fan switch from off to any speed setting
(Tracer ZN520 only)
Automatic Reset by the Controller
The controller includes an automatic diagnostic reset
function which attempts to automatically restore the unit
when a low temperature diagnostic occurs.
Note:
The controller implements the automatic
diagnostic reset function only once every 24 hours.
For the controller to increment the 24-hour timer,
you must maintain power to the controller. Cycling
power resets all timers and counters.
After the controller detects the first low temperature
diagnostic, the unit waits 30 minutes before invoking the
automatic diagnostic reset function. The automatic
diagnostic reset function clears the special diagnostic and
attempts to restore the controller to normal operation. The
controller resumes normal operation until another
diagnostic occurs.
Note:
The automatic diagnostic reset function does not
operate during the manual output test sequence.
If a special diagnostic occurs within 24 hours after an
automatic diagnostic reset, the controller must be
manually reset. Other possible methods of resetting
diagnostics are described in the sections that follow.
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
page 137
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
Table 78
and
Table 79
).
Controller Diagnostics
Table 78. 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.
