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SCXG-SVX01B-EN 117
Diagnostic
Troubleshooting Diagnostics
range for 10 continuous seconds, or after
a different SA pressure setpoint source is
user-defined.
Supply Air Temp Cool Setpoint Fail
Problem: The active supply air
temperature cooling setpoint is out of
range.
Reason for Diagnostic: The input
designated as the SA temp cooling
setpoint is out is out of range (temp < 35 F
or temp > 95 F).
UCM’s Reaction: The default HI-set SA
temp cooling setpoint becomes the active
SA temp cooling setpoint.
Reset Required: (PAR) An automatic reset
occurs after the SA temp cooling setpoint
input returns to within range for 10
continuous seconds, or after a different
SA temp cooling setopint selection
source is user-defined.
Supply Air Temp Heat Setpoint Fail
Problem: The active supply air
temperature cooling setpoint is out of
range.
Reason for Diagnostic: The input
designated as the SA temp heating
setpoint is out is out of range (Temp < 35
F or Temp > 185 F).
UCM’s Reaction: The default HI-set SA
temp heating setpoint becomes the
active SA temp heating setpoint.
Reset Required: (PAR) An automatic reset
occurs after the SA temp heating setpoint
input returns to within range for 10
continuous seconds, or after a different
SA temp heating setopint selection
source is user-defined.
Supply Air Temperature Failure
Problem: The supply air temperature
sensor input is out of range.
Check: Sensor resistance should be
between 830 ohms (200 F) and 345.7
Kohms (-40 F). If so, check field/unit wiring
between sensor and RTM.
Reason for Diagnostic: The unit is reading
a signal that is out of range for the supply
air temperature input on the RTM (temp.
< -55 F or temp > 209 F).
UCM’s Reaction: These unit functions are
disabled:
• supply air tempering
• economizing
• supply air temperature low limit function
(CV units)
• supply air temperature control heating
and cooling functions (VAV units)
Reset Required: (PAR) an automatic reset
occurs after the designated S/A
temperature input returns to its allowable
range. To prevent rapid cycling of the
diagnostic, there is a 10 second delay
before the automatic reset.
Supply Fan Failure
Problem: There is no supply airflow
indication after the supply fan has been
requested on.
Check: Check belts, linkages, etc. on the
Supply Fan assembly. If these are ok,
check field/unit wiring between RTM and
supply fan. If the supply fan will run in
service mode, then verify airflow proving
switch and wiring.
Reason for Diagnostic: The supply airflow
input is detected OPEN for 40 continuous
seconds during any period of time in
which the supply fan binary output is ON.
between 830 ohms (200 F) and
345.7Kohms (-40 F). If so, check field/unit
wiring between the sensor and MCM.
This input is ignored for up to 5 minutes
after the supply fan is first started, until
airflow is first detected.
UCM’s Reaction: “OFF or “Close”
requests are issued as appropriate to the
following functions;
a. Compressor staging/chilled water
control
b. Heat operation
c. Supply fan control and proof of
operation.
d. Exhaust fan control and proof of
operation
e. Exhaust actuator control
f. Economizer actuator control
g. IGV / VFD control
Reset Required: (PMR) A manual reset is
required anytime after the diagnostic is
set. The diagnostic can be reset at the HI,
Tracer Summit
®
, or by cycling power to
the RTM.
Supply Fan VFD Bypass Enabled
a. Data used (module,packet,byte,bit):
RTM
b. Activation conditions: supply fan VFD
bypass has been activated and supply
fan vfd bypass is installed.
c. Time to React: 10 sec < T < 20 sec
d. Diagnostic text (human interface
display)
SUPPLY FAN VFD BYPASS ENABLED”
e. Actions to be Initiated: NONE
f. Reset: The INFO diagnostic is cleared
when the supply fan VFD bypass is
deactivated.
T
TCI Module Comm Failure
Problem: The RTM has lost
communication with the TCI.
Check: Check field/unit wiring between
RTM and TCI module.
Reason for Diagnostic: The RTM has lost
communication with the TCI module.
UCM’s Reaction: All active commands
and setpoints provided by Tracer
Summit
®
through the TCI will be
cancelled and/or ignored. And where
Tracer Summit
®
has been designated as
setpoint source, local HI default setpoints
will be used.
Reset Required: (PAR) An automatic reset
occurs after communication has been
restored.
Tracer Communications Failure
Problem: The TCI has lost
communications with Tracer Summit
®
.
Check: Tracer Summit
®
(building control
panel) is powered up and running
properly. If so, check unit wiring between
TCI and Tracer Summit
®
(building control
panel).