Trane Tracer AH540 User Manual

Chapter 3 Input and Outputs
22 CNT-SVX05B-EN
returns to a valid input, the controller automatically clears the diagnostic
and allows two-pipe changeover operation.
Evaporator refrigerant temperature
The universal analog input configured as evaporator refrigerant tempera-
ture accepts a 10 kΩ thermistor input (see Table 74 on page 106). A valid
evaporator refrigerant temperature is not required for DX cooling opera-
tion but does aid in protecting condensing unit compressors.
When a valid evaporator refrigerant temperature input is available to the
controller, it is used to determine if the DX cooling capacity should be
decreased to prevent low refrigerant temperatures. This function is
referred to as defrost operation (see “Defrost operation” on page 65). Low
refrigerant temperatures indicate frost conditions on the evaporator and
therefore cooling capacity must be reduced to defrost the coil.
When the evaporator refrigerant temperature input is established, the
controller generates an Evap Refrigerant Temp Failure diagnostic if the
signal is no longer valid, but the diagnostic has no affect on controller
operation. If the sensor returns to a valid input, the controller automati-
cally clears the diagnostic.
Generic temperature input
The universal analog input configured as generic temperature accepts a
10 kΩ thermistor input. The input can be used in a variety of applications
using Tracer Summit. This input has no effect on the controller operation
but will report a Generic Temperature Failure diagnostic message if the
input becomes invalid or out or range. The diagnostic automatically reset
when the input is valid or in range.
J43: Duct static pressure
The duct static pressure input (terminal J43) interfaces with a special-
ized pressure transducer only. When a valid duct static pressure value
(either hard-wired or communicated) exists and a variable-air-volume
supply fan is present, the controller uses this value for duct static pres-
sure control.
When a duct static pressure is established, the controller generates a
Duct Static Press Failure diagnostic if the signal is no longer valid, and
shuts down the unit. When the sensor returns to a valid input, the con-
troller automatically clears the diagnostic and allows the unit to resume
operation.
The Tracer AH540/541 controller, if configured for variable-air-volume
control, cannot operate without a valid duct static pressure input. When
the sensor returns to a valid input, the controller resumes unit operation.
The controller is not required to have a duct static pressure input for con-
stant-volume space temperature or constant-volume discharge air tem-
perature control.

Trane Tracer AH540 Specifications

General

Brand	Trane
Model	Tracer AH540
Category	Controller
Language	English