Trane SCXG-SVX01B-EN Maintenance diagnostics, VOM Communications Failure, WSM Communications Fail

Maintenance diagnostics

Reset Required: (PAR) An automatic reset occurs after communication between Tracer Summit and the LCI-I is restored.

U

Unit HI Communications Failure Problem: The RTM has lost communication with the unit mounted (local) human interface (HI).

Check: Field/unit wiring between RTM hand local HI.

Reason for Diagnostic: The RTM has lost communication with the unit-mounted human interface.

UCM Reaction: A fail-safe function in the HI will cause the following sequence:

a. disallow any interaction between the HI and the RTM (or any other modules),

b. render all HI keystrokes ineffective

c. cause the following message to display on the unit-mounted HI display: “Local HI communications loss. Check comm link wiring between modules.” If the unit has a remote HI option, then this diagnostic will display as any other automatic reset diagnostic.

Reset Required: (INFO) An automatic reset occurs after communication is restored between the RTM and the HI. When the failure screen clears, the general display restores to allow the HI to interact with the RTM again.

Unoccupied Zone Cool Setpoint Failure Problem: The unoccupied zone cooling setpoint input is out of range.

Reason for Diagnostic: The input designated as the unoccupied zone cooling setpoint source is out of range (temp < 45°F or temp > 94°F).

UCM Reaction: The active unoccupied zone cooling setpoint reverts to the default value.

Reset Required: (PAR) An automatic reset occurs after the designated unoccupied zone cool setpoint input returns to its allowable range for 10 continuous seconds, or after the user defines a

different, valid unoccupied zone cool setpoint selection source.

Unoccupied Zone Heat Setpoint Failure Problem: The unoccupied zone heating setpoint input is out of range.

Reason for Diagnostic: The input designated as unoccupied zone heating setpoint source is out of range (temp < 45 F or temp > 94 F).

UCM 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: The RTM has lost communication with the VCM.

UCM 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 deenergize 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. communications with the VOM.

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 orV > 420 mV, during operation: V < 40 mV or V > 0.75 V).

UCM 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.

UCM Reaction:Ventilation override actions will not be allowed, and the VO Output relay will be deenergized.

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: The RTM has lost communication with the WSM.

UCM Reaction: The UCM will react as if a freezestat has occurred by issuing:

•An “all heat on” or “mod output full open” request to “heat control”

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