BCXC-SVX01A-EN
51
Maintenance
Diagnostics
Translating Multiple
Diagnostics
The controller senses and records each
diagnostic independently of other
diagnostics. It is possible to have multiple
diagnostics present simultaneously. The
diagnostics are reported in the order
they occur.
Possible diagnostics include:
• Low temperature detection
• Condensate overflow
• Low air flow - fan status
• Discharge air temp limit
• Space temperature failure
1
• Entering water temp failure
1
• Discharge air temp failure
1
• Outdoor air temp failure
1
• Local setpoint failure
1
• Local fan mode failure
1
• CO
2
sensor failure
1
• Generic AIP failure
1
• Humidity input failure
1
• Defrosting compressor lockout
1
• Maintenance required
• Invalid Unit Configuration
• Generic temperature failure
• Discharge air low limit
Note: Non-latching diagnostics auto-
matically reset when the input is
present and valid.
Resetting Diagnostics
There are six ways to reset unit
diagnostics:
1. Automatically by the controller
2. By initiating a manual output test at the
controller
3. By cycling power to the controller
4. By using a building automation system
(Tracer ZN510 or ZN520 only)
5. By using the Rover service tool
6. By using any other communicating
device able to access the controller’s
diagnositc reset input (Tracer ZN510 or
ZN520 only)
7. 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
temperatuare diagnostic, the unit waits
30 minutes before invoking the auto-
matic diagnostic reset function. The
automatic diagnostic reset function
clears the special diagnostic and at-
tempts 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.
IIf a special diagnostic occurs within 24
hours after an automatic diagnostic
reset, the controller must be manually
reset. Other possible methods of reset-
ting 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
49 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 (Tracer
ZN510 or ZN520 Only)
Some building automation systems can
reset diagnostics in the Tracer ZN510 or
ZN520 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
®
ZN520 controller. For more
complete information, refer to the
Rover™ Installation, Operation, and
Programming manual.
Diagnostic Reset (Tracer ZN510 or
ZN520 Only)
Any device that can communicate the
network variable nviRequest
(enumeration “clear_alarm”) can reset
diagnostics in the Tracer
ZN510 or
ZN520 controller. The controller also
attempts to reset diagnostics whenever
power is cycled.
Cycling the Fan Switch (Tracer ZN520
Only)
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).
Trane’s Service Tool, Rover™
Rover™, Trane’s service tool, can reset
diagnostics present in the controller. For
complete information about Rover™,
refer to Trane publication
EMTX-IOP-2
Rover Installation, Operation and
Programming Guide.
Alarm Reset
Any device that can communicate alarm
reset information can reset diagnostics
present in the controller.
