Trane Tracer VV550 User Manual

CNT-SVX17G-EN 15
Inputs and Outputs
Primary Air Temperature/Discharge Air temperature Analog Input
The controller senses the primary or discharge air temperature input with a hardwired
10k thermistor. The primary/discharge air temper
ature analog input can be configured
as either primary air temperature or discharge air temperature and applied as:
• Primary supply air temperature input for stand-alone changeover control and local
re
heat lockout. The 10k thermistor is upstream from the VAV hea
ting and cooling
capacity;
• Discharge air temperature input for reheat control (preconditioning outdoor air in a
ventilat
ion flow control job). The discharge air temperature is used as feedback to the
control algorithm that is influencing the discharge air temperature. This is discharge
air control for units configured as ventilation flow control units. The 10k thermistor
is dow
nst
ream of the VAV reheat capacity.
Either configuration also provides monitor
i
ng and diagnostics.
The controller can receive the primary air temperature as either a local analog input or
as a commun
icated value. If both are present, the controller uses the communicated
source temperature. If neither is present, the controller uses configuration to assume a
primary air condition, either hot or cold.
The space temp controller or a flow-tracking controller can operate without a valid
discha
rge
air temperature analog input. Table 9 shows that the impact of discharge air
temp
erature loss depends on the control algorithm configuration. If a valid discharge air
temperature is present, then disappears, then returns to the valid range, the controller
automatically resets and attempts to run normally.
Table 9. Discharge air temperature loss impact and control algorithm configuration
Discharge air
temperature
failure
Type of control Unit operation Air valve Fan Reheat
Open or short
afte
r being valid
Space
temperature
controller
Normal operation; discharge air
te
mperature failure diagnostic
Normal Normal Normal
Ventilation flow
controll
er with
reheat
Shutdown; discharge air temperature
failure diagnostic
Closed Do not
care
Off
Ventilation flow
controll
er without
reheat
Normal operation; discharge air
temperature failure diagnostic
Normal Do not
care
Do not
care
Flow tracking
con
troller
Normal operation; discharge air
temperature failure diagnostic
Normal Do not
care
Do not
care
This sequence is ignored by and can be overridden by the following sequences listed in
priority from highest to lowest. For more information on control sequence descriptions,
refer to “Control Sequences,” p. 8.
1. Power up and reset sequence (highest priority)
2. Manufacturing test
3. Unit shutdown
4. Emergency override

Trane Tracer VV550 Specifications

General

Brand	Trane
Model	Tracer VV550
Category	Controller
Language	English