Bi3; Low Coil Temp Detection; Bi4; Frost Detection; Bi5; Fan Status; Analog Inputs - Trane Tracer UC400 Installation, Operation And Maintenance Manual

condensate reaches the trip point, the UC400 Controller detects the condition and generates a
Condensate Overflow diagnostic.

BI3; Low Coil Temp Detection

Low Coil Temperature Detection BI3 protects the coil from freezing. If BI3 is wired to a binary low
coil temperature detection device (freeze-protection switch) and a low coil temperature condition
exists, the UC400 Controller detects the condition and generates a Low Coil Temperature
Detection diagnostic.
N N o o t t e e : : This input is for Hydronic or Steam Coils only.

BI4; Frost Detection

Frost detection BI4 detects conditions that produce frost on the coil surface. When these
conditions are present, the UC400 Controller detects the condition and generates a Frost
Detection Input alarm.
N N o o t t e e : : This input is for only DX.

BI5; Fan Status

Fan Status BI5 provides feedback to the UC400 Controller regarding the operating status of the
fan. If BI5 is wired to a fan status switch, and the input indicates that the fan is not operating
when the controller has the fan controlled to ON, the controller generates a Low Airflow Supply
Fan Failure diagnostic.

Analog Inputs

The UC400 Controller has seven (7) analog inputs.

Ground Terminals

Use the

AI1; Space Temperature

Space Temperature AI1 functions as the local (hard wired) space temperature input. The UC400
Controller receives the space temperature as a resistance signal from a 10 kΩ thermistor in a
standard Trane space temperature sensor that is wired to analog input AI1. A space temperature
value communicated by means of a BACnet link, can be used for controllers operating on a BAS.
When both a hard wired and communicated space temperature value are present, and in service,
the controller uses the communicated value.
If neither a hard wired nor a communicated space temperature value is present, the space
temperature local and active points go into a fault state and generates an alarm. If neither the
hard wired or communicated space temperature are valid, the controller runs discharge air
control as backup. The space temperature setpoint is used as the discharge air temperature
setpoint. At the same time, the air valve modulates and reheat is used (if needed) to control the
discharge air temperature to the DAT setpoint.

AI2; Space Temperature Local Setpoint

Space Temperature Local Setpoint AI2 functions as the local (hard wired) space temperature
setpoint input for applications utilizing a Trane space temperature sensor with a temperature
setpoint thumbwheel or digital setpoint input. A setpoint value communicated by means of a
BACnet link, can be used for controllers operating on a BAS. If both hard wired and
communicated setpoint values are present, and in service, the UC400 Controller uses the
communicated value.
In addition, the controller can be configured to use the local (hard wired) input value instead of
the communicated value using the Tracer TU service tool. If neither a hard wired nor a
communicated setpoint value is present, the controller uses the space temperature setpoint
default analog value, which is configured using the Tracer TU service tool. If a valid local setpoint
value is established, and then is no longer present, the controller generates a Space Temperature
Setpoint Local alarm.
BAS-SVX48H-EN
terminal as the common ground for all space temperature sensor analog inputs.
T T y y p p i i c c a a l l A A p p p p l l i i c c a a t t i i o o n n s s a a n n d d T T e e r r m m i i n n a a t t i i o o n n s s
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