Trane HUV Installation, Operation And Maintenance Manual page 91

Using Trane's Service Tool, Rover (Tracer
ZN520)
Rover, Trane's service tool, can reset diagnostics present in
the controller and troubleshoot the unit. For more
information, refer to the Trane publication
EMTX-SVX01G-EN (Rover Service Tool: Installation,
Operation, and Programming Guide), or the most recent
revision.
Diagnostic Reset (Tracer ZN520)
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 (Tracer ZN520)
Cycle the fan speed switch from Off to any speed and the
controller resets all diagnostics. Diagnostics may recur
immediately if the problem still exists.
Table 31. Fan outputs do not energize (Tracer ZN520)
Probable
Cause Explanation
Random start After power-up, the controller always observes a random
start that varies observed between 0 and 25 seconds. The
controller remains off until the random start time expires.
Power-up When power-up control wait is enabled (non-zero time), the
control wait controller remains off until one of two conditions occurs:
1. The controller exits power-up control wait once it receives
communicated information.
2. The controller exits power-up control wait once the
power-up control wait time expires.
Cycling fan When the fan mode switch is in the auto position, the unit
operation fan cycles off when there is no call for heating or cooling. The
heating/cooling sources cycle on or off periodically with the
unit fan to match the capacity according to pulse-width-
modulation (PWM) logic.
Unoccupied The fan cycles with capacity when the unit is in unoccupied
operation mode. This occurs even if the unit is in continuous fan
operation. While unoccupied, the fan cycles on or off with
heating/cooling to provide varying amounts of heating or
cooling to the space to match the to pulse-width-modulation
(PWM) logic.
Fan mode off When using the local fan mode switch to determine the fan
operation, the off position controls the unit fan to off.
Requested It is possible to communicate the operating mode (such as
mode: off off, heat, and cool) to the controller. When "off" is
communicated to the controller, the unit controls the fan to
off. The unit is not capable of heating or cooling when the
controller is in this mode.
Diagnostic A specific list of diagnostics effects fan operation. For more
present information, see "Diagnostics," p.
No power to If the controller does not have power, the unit fan will not
the controller operate. For the controller to operate normally, it must have
an input voltage of 24 Vac. When the green LED is off
continuously, the controller does not have sufficient power
or the controller has failed.
Manual output The controller includes a manual output test sequence to
test verify binary output operation and the associated wiring.
However, based on the current step in the test sequence, the
unit fan may not be powered on. Refer to
Test (Tracer ZN520)," p.
Unit wiring The wiring between the controller outputs and the fan relays
and contacts must be present and correct for normal fan
operation. Refer to the typical unit wiring diagrams.
UV-SVN02C-EN
88.
"Manual Output
90.
Table 32. Valves stay closed (Tracer ZN520)
Probable
Cause Explanation
Normal The controller opens and closes the valves to meet the unit
operation capacity requirements.
Requested It is possible to communicate the operating mode (such as
mode: off off, heat, and cool) to the controller. When off is
communicated to the controller, the unit controls the fan to
off. The unit is not capable of heating or cooling when the
controller is in this mode.
Valve override The controller can communicate a valve override request.
This request affects the valve operation.
Manual output The controller includes a manual output test sequence to
test verify analog and binary output operation and the associated
wiring. However, based on the current step in the test
sequence, the valves may not be open. Refer to
Output Test (Tracer ZN520)," p.
Diagnostic A specific list of diagnostics affects valve operation. For more
present information, see "Diagnostics," p.
Sampling The controller includes entering water temperature
logic sampling logic that automatically invokes during 2-pipe or
4-pipe changeover. It determines when the entering water
temperature is either too cool or too hot for the desired
heating or cooling mode.
Unit The controller must be properly configured based on the
configuration actual installed end devices and application. When the unit
configuration does not match the actual end device, the
valves may not work correctly.
No power to If the controller does not have power, the valves do not
the controller operate. For the controller to operate normally, it must have
an input voltage of 24 Vac. When the green LED is off
continuously, the controller does not have sufficient power,
or the controller has failed.
Unit wiring The wiring between the controller outputs and the valve(s)
must be present and correct for normal valve operation.
Refer to the typical unit wiring diagrams.
Table 33. Valves stay open (Tracer ZN520)
Probable
Cause Explanation
Normal The controller opens and closes the valves to meet the unit
operation capacity requirements.
The controller can communicate a valve override request to
Valve override
affect the valve operation.
The controller includes a manual output test sequence that
Manual output
verifies analog and binary output operation and the
test
associated wiring. However, based on the current step in the
test sequence, the valves may be open. Refer to
Output Test (Tracer ZN520)," p.
Diagnostic A specific list of diagnostics affects valve operation. For more
present information, see "Diagnostics," p.
Sampling The controller includes entering water temperature
logic sampling logic that automatically invokes during 2-pipe or
4-pipe changeover to determine if the entering water
temperature is correct for the unit operating mode.
The controller must be properly configured based on the
Unit
actual installed end devices and application. When the unit
configuration
configuration does not match the actual end device, the
valves may not work correctly.
The wiring between the controller outputs and the valve(s)
Unit wiring
must be present and correct for normal valve operation.
Refer to the typical unit wiring diagrams.
Diagnostics
"Manual
90.
88.
"Manual
90.
88.
91