BCXC-SVX01B-EN 75
Diagnostics
• 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
• 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
Resetting Diagnostics
There are seven 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 diagnostic 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 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.
1
Non-latching diagnostics automatically reset when the input is present and valid.
