Unit Protection Strategies; Smart Reset; Low Coil Temperature Protection; Condensate Overflow - Trane Tracer UC400 Installation, Operation And Maintenance Manual

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The space relative humidity can be a BAS-communicated value or come directly from a wired
relative humidity sensor. The UC400 Controller begins to dehumidify the space when the space
humidity exceeds the humidity setpoint. The controller continues to dehumidify until the sensed
humidity falls below the setpoint, minus the relative humidity offset.

Unit Protection Strategies

The following unit protection strategies are initiated when specific conditions exist in order to
protect the unit or building from damage:
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Smart Reset

The UC400 Controller automatically restarts a unit that is locked out as a result of a Low Coil
Temp Detection (BI3) diagnostic. Referred to as smart reset, this automatic restart occurs 30
minutes after the diagnostic occurs. If the unit is successfully restarted, the diagnostic is cleared.
If the unit undergoes another Low Coil Temp Detection diagnostic within a 24-hour period, the
unit is locked out until it is manually reset.
N N o o t t e e : : Freeze protection will also perform a smart reset.

Low Coil Temperature Protection

Refer to the section,
Smart Reset.

Condensate Overflow

Refer to the section,

Fan Status

In 1-, 2-, and 3-speed fans, the status is based on the statuses of the supply fan output multi-state
and analog points dedicated to fan control. The fan status is reported as HIGH, MEDIUM, LOW,
and as a percentage, whenever the fan is running. The fan status is reported as OFF whenever
the fan is not running. In addition, a fan status switch can be connected to binary input 5 (BI5) to
monitor the status of the fan for belt-driven or direct-driven units (except Trane Macon factory
ECM fan motor units). The fan status switch provides feedback to the controller as follows:
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This manual diagnostic discontinues unit operation until the diagnostic has been cleared from
the UC400 Controller. If a diagnostic reset is sent to the unit and the fan condition still exists, the
controller attempts to run the fan for one (1) minute before generating another diagnostic and
performing a unit shutdown. A diagnostic reset can be sent to the unit from the Tracer TU Alarms
BAS-SVX48H-EN
The space relative humidity is valid.
Smart Reset
Low Coil Temperature Protection
Condensate Overflow
Fan Status
Fan Off Delay
Filter Maintenance Timer
Freeze Avoidance
Freeze Protection (Discharge Air Temperature Low Limit)
"BI3; Low Coil Temp Detection," p. 15
"BI2; Condensate Overflow," p.
If the fan is not operating when the UC400 Controller has the fan controlled to ON, the unit
generates a Low Airflow-Supply Fan Failure diagnostic.
If the UC400 Controller energizes the fan output for one (1) minute, and the fan status switch
indicates no fan operation, then the controller performs a unit shutdown and generates a Low
Airflow-Supply Fan Failure diagnostic.
If the fan has been operating normally for one minute, but the fan status switch indicates no
fan operation, the same diagnostic is generated.
S S e e q q u u e e n n c c e e o o f f O O p p e e r r a a t t i i o o n n
and to the previous section about
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