Tracer UC 400 Controller
146
UNT-SVX07E-EN
Troubleshooting UC400 Controller
Fans
Generic AIP failure
Invalid or missing value for generic
analog input.
• Fan
Unaffected
• Valves
Unaffected
• Outdoor air damper
Unaffected
• DX cooling/electric heat
Unaffected
Informational
Local fan mode failure
Invalid or missing fan-speed switch
(reverts to default fan speed)
.
• Fan
Unaffected
• Valves
Unaffected
• Outdoor air damper
Unaffected
• DX cooling/electric heat
Unaffected
Automatic
Local setpoint failure
Invalid or missing value for zone
temperature setpoint
(reverts to default
setpoint)
.
• Fan
Unaffected
• Valves
Unaffected
• Outdoor air damper
Unaffected
• DX cooling/electric heat
Unaffected
Automatic
Note:
1
For detailed information about zone temperature control methods, refer to
“Zone Temperature Control,” page 115
Table 87.
Diagnostics generated by UC4000 controller
Diagnostic
Probable Cause
Consequences
Diagnostic Type
Table 88. Fan does not energize
Probable Cause
Explanation
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 applicable wiring diagram.
Failed end device
The fan motor and relay must be checked to ensure proper operation.
Normal operation
The fan will turn
OFF
when:
• The controller receives a communicated off signal
• The fan-speed switch is set to
OFF
if no communicated value is present
• Specific diagnostics are generated
• The default fan speed is set to
OFF
and the fan is operating in the Auto mode.
If the controller is in unoccupied mode, the fan cycles between
OFF
and the highest fan speed.
No power to
the controller
If the controller does not have power, the unit fan does not operate. For the controller to operate normally, it must
have an input voltage of 24 Vac. If the Marquee/Power LED is
OFF
continuously, the controller does not have
sufficient power or has failed.
Diagnostic present
Several diagnostics affect fan operation. For detailed information about these diagnostics, refer to
Table 87,
page 145
.
Unit configuration
The controller must be properly configured based on the actual installed end devices and application. If the unit
configuration does not match the actual end device, the fans may not work correctly.
Random start observed
After power-up, the controller always observes a random start from 5 to 30 seconds. The controller remains
OFF
until the random start time expires.
Cycling fan operation/
continuous
The controller continuously operates the fan when in the occupied, occupied standby, or occupied bypass mode.
When the controller is in the unoccupied mode, the fan is cycled between high speed and
OFF
with capacity.
Unoccupied operation
Even if the controller is configured for continuous fan operation, the fan normally cycles with capacity during
unoccupied mode. While unoccupied, the fan cycles
ON
or
OFF
with heating/cooling to provide varying amounts
of heating or cooling to the space.
Fan mode off
If a local fan mode switch determines the fan operation, the
OFF
position controls the fan to off.
Requested mode off
The user can communicate a desired operating mode (
such as
OFF
, heat, and cool
) to the controller. If
OFF
is
communicated to the controller, the unit controls the fan to off. There is no heating or cooling.
