102
SCXF-SVX01T-EN
Category Diagnostic
Controls
Reaction
The active unoccupied zone heating setpoint reverts to the default value.
Reset
Required
(PAR) An automatic reset occurs after the designated unoccupied zone heat setpoint input returns to its allowable range for 10 continuous
seconds, or after the user defines a different, valid unoccupied zone heating setpoint selection source.
V
VCM Communication Failure
Problem The RTM has lost communication with the VCM.
Verify Check field/unit wiring between RTM and VCM.
Reason for
Diagnostic
RTM has lost communication with VCM.
Controls
Reaction
All active commands and setpoints provided by the VCM are canceled and/or ignored. A fail-safe function in the VCM will cause all outputs to
de-energize and/or set to zero. The outside air damper minimum position function will revert to using the O/A flow compensation function if O/A
flow compensation is enabled or set to the default minimum position function if O/A flow compensation is disabled or not available.
Reset
Required
(PAR) An automatic reset occurs after communication is restored.
Velocity Pressure Sensor Failure
Problem
The velocity pressure input signal is out of range.
Check
Check field/unit wiring between sensor and VCM.
Reason for
Diagnostic
The unit is reading a signal that is out of range for the velocity pressure transducer input (during calibration: V < 40 mV or V > 420 mV, during
operation: V < 40 mV or V > 0.75 V).
Reaction
The minimum airflow control function is disabled. The outside air damper minimum position function reverts to using the O/A flow
compensation function if O/A flow compensation is enabled or to the default minimum position function if O/A flow compensation is disabled or
not available.
Reset
Required
(PAR) An automatic reset occurs after the designated space pressure transducer sends a signal within range for 10 continuous seconds.
VOM Communications Failure
Problem The RTM has lost communication with the VCM.
Check
Field/unit wiring between RTM and VCM.
Reason for
Diagnostic
The RTM has lost communications with the VOM.
Controls
Reaction
Ventilation override actions will not be allowed, and the VO Output relay will be de-energized.
Reset
Required
(PAR) An automatic reset occurs after communication has been restored.
W
WSM Communications Fail
Problem The RTM has lost communication with the WSM.
Check
Field/unit wiring between RTM and WSM.
Reason for
Diagnostic
RTM has lost communication with WSM.
Controls
Reaction
UCM will react as if a freezestat has occurred by issuing:
• “All heat on” or “mod output full open” request to “heat control”
• A “fan off” request to “supply fan control”
• “Close damper” request to “economizer actuator control”
• Water pump to turn on and position all water valves to provide maximum flow through all water source heat exchangers
• Disables preheat function if WSM mixed air temp sensor is selected as preheat sensor
Diagnostics
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