Trane S*HF*20-75 Troubleshooting Manual page 131

Table 11: Diagnostics Troubleshooting Chart (continued)
Minimum Outdoor Air
Flow Setpoint Failure
Used With: Fresh Air
Measurement (VCM)
option.
Module: VCM
Mode Input Failure
Module: RTM
Morning Warmup
Setpoint Failure
Module: RTM
NSB Panel
Communication Failure
Module: NSB Panel
RT-SVP07B-EN
Problem: The GBAS input
assigned to Minimum
Outdoor Air Flow Setpoint
is out of range. (OAFlowStp
is < 0 or OAFlowStp > Max
1
Unit Airflow
Check: Wiring and
external devices on the
associated GBAS input.
1
See Setpoints menu Min
OA Flow Setpoint for max
unit airflows table.
Problem: The RTM Mode
input is out of range. (R <
1k ohm or R > 40k ohm)
Check: Mode input
resistance should be
between 1 Kohm and 40
Kohms. If so, check field/
unit wiring between Sensor
and RTM.
Problem: The GBAS input
assigned to MWU Setpoint
is out of range (Temp < 50
F or Temp > 90 F).
Check: Wiring and
external devices on the
associated GBAS input.
Problem: The RTM has lost
communications with the
NSB Panel (Night SetBack
Panel or programmable
zone sensor).
Check: Check field/unit
wiring between RTM and
NSB Panel.
The Active Minimum OA
Flow Setpoint reverts to the
default Minimum OA Flow
Setpoint of the Human
Interface.
The system mode reverts
to the default (HI set)
System Mode.
The Active MWU Setpoint
reverts to the default
MWUSetpoint from the
Human Interface.
a. The unit reverts to the
next lower priority mode
switching source (typically
the HI default mode).
b. if the NSB Panel Zone
Sensor is the designated
sensor source for any
functions, those functions
are disabled.
DIAGNOSTICS Menu
(PAR) An automatic reset
occurs after the Minimum
OA Flow Setpoint input
returns to within range for
10 continuous seconds, or
after a different, valid
Active Minimum OA Flow
Setpoint value is specified
(BAS/Network).
(INFO) An automatic reset
occurs after the Mode input
returns to its allowable
range for 10 seconds.
(PAR) An automatic reset
occurs after the GBAS input
assigned to the MWU
Setpoint input returns to
within range for 10
continuous seconds, or
after a different, valid MWU
Setpoint source is applied
(BAS/Network).
(PAR) An automatic reset
occurs after
communication has been
restored.
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