100
SCXF-SVX01T-EN
Category Diagnostic
Controls
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 setpoint 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 ohms (-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).
Controls
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 is 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
runs 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 345.7 ohms (-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 starts, until airflow is first detected.
Controls
Reaction
“Off” or “Close” requests are issued as appropriate to the following functions;
• Compressor staging/chilled water control
• Heat operation
• Supply fan control and proof of operation
• Exhaust fan control and proof of operation
• Exhaust actuator control
• Economizer actuator control
• 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
Data used
(module,
packet, byte,
bit)
RTM
Activation
conditions
Supply fan VFD bypass has been activated and supply fan vfd bypass is installed.
Time to React 10 sec < T < 20 sec
Diagnostic
text
(human
interface
display)
“SUPPLY FAN VFD BYPASS ENABLED”
Actions to be
Initiated
NONE
Diagnostics
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