Trane S*HF*20-75 - Page 132

132 RT-SVP07B-EN
DIAGNOSTICS Menu
NSB Panel Zone Temp
Sensor Failure
Module: NSB Panel
Problem: The NSB Panel's
zone temp sensor input is
out of range. (This input is
at the NSB Panel, not on the
Rooftop unit itself).
Check: If an external
sensor is connected to the
NSB Panel zone sensor
input the internal NSB
Panel zone sensor should
be disabled, therefore
verify external sensor’s
resistance. If in valid range,
check wiring between
sensor and the NSB Panel.
a. If the external sensor
has failed the NSB will
revert to its local value and
no diagnostic will be
generated.
b. If the local sensor has
failed also, or is the only
sensor of the two being
used, the unit will generate
the diagnostic and set all of
the associated functions to
disabled.
(PAR) An automatic reset
occurs after the NSB
Panel’s sensor returns to
within range for 10
continuous seconds, or
after a different, valid
Active Zone Temp Sensor
value is specified (BAS/
Network).
OA Humidity Sensor
Failure
Used With: Comparative
Enthalpy option.
Module: RTM
Problem: The outside air
humidity sensor data is out
of range (Humidity < 10%
or Humidity > 90%).
Check: Check field/unit
wiring between RTM and
the sensor.
The Economizer Enable r.e
Enthalpy function reverts
to Dry-Bulb Temperature
changeover (“Level 1”)
control.
(PAR) An automatic reset
occurs after the OA
Humidity input returns to
its allowable range for 10
seconds.
OA Temperature Sensor
Failure
Used With: Comparative
Enthalpy, DX cooling,
Energy Recovery Wheel
options.
Module: RTM
Problem: The RTM OA
Temperature Sensor has
been assigned to at least
one function, and this
sensor signal is out of range
(Temp < -55 F or Temp >
209 F).
Check: The HI value and
wiring between the RTM
module and the sensor.
Removing the plug from the
RTM module there should
be no shorts, opens and
sensor resistance should be
between 830 ohms and
345.7Kohms.
Unit functions that are
disabled include:
a. Low Ambient
Compressor Lockout
b. The Outside Air Damper
drives to minimum
position.
c. On VAV units with SA
Temp Reset type selected
as OA Temp Reset, the
Reset type reverts to NONE
for the duration of the
failure.
(PAR) An automatic reset
occurs after the OA Temp
input returns to its
allowable range. In order to
prevent rapid cycling of the
Diagnostic, there is a 10
second delay before the
automatic reset.
Occupied
Dehumidification
Setpoint Failure
Module: RTM
Problem: The GBAS input
assigned to Occupied
Dehumidification Setpoint
is out of range (Humidity <
10% or Humidity > 90%).
Check: Wiring and
external devices on the
associated GBAS input.
The Active Occupied
Dehumidification Setpoint
reverts to the default
Occupied Dehumidification
Setpoint from the Human
Interface.
(PAR) An automatic reset
occurs after the GBAS input
assigned to the Occupied
Dehumidification Setpoint
input returns to within
range for 10 continuous
seconds, or after a
different, valid Occupied
Dehumidification Setpoint
source is applied (BAS/
Network).
Table
11: Diagnostics Troubleshooting Chart (continued)