Zone Sensors; Space Temperature Measurement; Zone Sensor Setpoint Thumbwheel; Fan Mode Switch - Trane Tracer AH540 Setup And Operation

Chapter 3 Input and Outputs
28

Zone sensors

The controller accepts the following zone sensor inputs:
Space temperature measurement (10 kΩ thermistor)
•
Zone sensor setpoint thumbwheel (either internal or external on the
•
zone sensor module) (see Table 73 on page 106)

Fan mode switch

•
Timed override On request
•
Timed override Cancel request
•
• Communication jack
Service pin message request
•

Space temperature measurement

Trane zone sensors use a 10 kΩ thermistor to measure the space temper-
ature. Typically, zone sensors are wall-mounted in the room and include a
space temperature thermistor. A valid space temperature input is
required for the controller to operate in space temperature control.
If both a hard-wired and communicated space temperature value exist,
the controller ignores the hard-wired space temperature input and uses
the communicated value.

Zone sensor setpoint thumbwheel

Zone sensors with an internal or external setpoint thumbwheel (1 kΩ)
provide the Tracer AH540/541 controller with a local setpoint (50ºF to
85ºF [10ºC to 29.4ºC]). An internal setpoint thumbwheel is concealed
under the front cover of the zone sensor. To access it, remove the zone sen-
sor cover. An external setpoint thumbwheel (when present) is accessible
from the front cover of the zone sensor.
See "Zone sensor setpoint thumbwheel" on page 36 for an explanation of
how the controller determines the setpoint.
Fan mode switch
The zone sensor fan mode switch provides the controller with a fan
request signal (Off, Auto). If the fan control request is communicated to
the controller, the controller ignores the hard-wired fan mode switch
input and uses the communicated value.
The zone sensor fan mode switch input can be enabled or disabled
through configuration using the Rover service tool. If the zone sensor
switch is disabled, the controller resorts to the Auto fan mode.
When the fan mode switch is placed in the Off position, the controller
does not control any unit capacity. The unit remains powered and all out-
puts are driven Closed or Off.
Upon a loss of signal on the fan speed input, the controller reports a diag-
nostic and reverts to using the Auto fan mode of operation.
CNT-SVX05B-EN