Trane MUA-SVP01A-EN manual Diagnostics, Critical Fault Codes, Fault Code Low Discharge Temperature

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Diagnostics

Critical Fault Codes

This section should assist the user in troubleshooting critical fault codes messages that have been displayed on the local user interface. These faults require the operator to correct the condition and reset the alarm before normal unit operation resumes.

FAULT CODE: Low Discharge Temperature

PROBLEM: The controller has detected a low temperature at the fan outlet and has shut off the unit. See Freezestat section of this manual.

SOLUTION: If burner was operating prior to shutdown (check prior alarm log)

1.Is the outside air (OA Temp) or room air (Room Temp) displayed on the BACview remote, reading 150°F or more?

–Yes. That sensor circuit or the sensor itself is shorted. Unplug the input jack from the AdaptAire controller. Did the display change to -40°F or less?

–No. There is a short in the controller input. Replace the controller.

–Yes. Disconnect the sensor wiring at the sensor. Connect an ohmmeter to the sensor. If it is shorted replace the sensor. At 77°F the resistance should be 10K?. See thermistor output curve for other temperatures. If it is not shorted, there is a short in the wiring between the sensor and the input plug. Determine cause and rectify. Refer to Appendix II for a typical 10K? thermistor output curve.

–No. Continue.

2.Is the discharge air temperature (DA Temp), displayed on the BACview remote, reading -40°F or less?

–Yes. That sensor circuit or the sensor itself is open. Jumper the input for the sensor. Did the display change to 150°F or more?

–No. There is an open in the controller input. Replace the controller.

–Yes. Disconnect the sensor wiring at the sensor. Connect an ohmmeter to the sensor. If it is open replace the sensor. At 77°F the resistance should be 10K?. See thermistor output curve for other temperatures. If it is not open, there is a break in the wiring between the sensor and the input plug. Determine cause and rectify.

–No. Continue

3.Reset the alarm. Check and note the DC voltage at output for the gas valve modulation. Set the Heating Setpoint for 90°F. Set the MAX DAT and MIN DAT Setpoints for 130°F. Did the Burner VDC, displayed on the BACview remote, increase?

–No. Unless the outside air temperature is extremely warm the Burner VDC should have increased to 7.5VDC or more. Close the manual main gas

MUA-SVP01A-EN • Direct-Fired Indoor and Outdoor Units

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Contents Controls Programming Guide JanuaryOverview Networking Direct-Fired Indoor and Outdoor Units MUA-SVP01A-EN Contents Contents Unit Operating Modes MDT ControlsMRT Controls MRT-Pro ControlsUnit Operating Modes MRT-Expert Controls Unit Operating Modes General Burner Control Heating ModeHeating/Ventilating/Cooling Operating Modes Unit Operating Modes Ventilation Mode Cooling Mode M P E R a T U R E S EManual Mode Damper Control ModesMixed Air Temperature Mode Building Pressure Mode Minimum Ventilation Functions100% Outside Air FreezestatUser Configured PID Control Direct Acting85ºF Reverse Acting Direct actingReverse acting Unit Resets Multiplexed InputsClock Set Fault Code Low Discharge Temperature DiagnosticsCritical Fault Codes Diagnostics Direct-Fired Indoor and Outdoor Units MUA-SVP01A-EN Fault Code Safety Circuit Open Fault CODEBurner Status SOLUTIONIf fan is running check prior alarm logFault Code Burner Hand Diagnostics Non-Critical Fault Codes Fault Code Flame FailureSolution If fan is not running Fault Code Unit off/Fan onSolution If fan is running Solution If fan/motor is not running Fault CODEUnit on/Fan offSOLUTIONIf fan/motor is running Fault Code Check Airflow Switches Fault Code Clogged Filter Switch SOLUTIONIf clogged filter switch is closingFault CODEEnergy Save Mode SOLUTIONIf setpoints are misadjustedSOLUTIONIf setpoints are not misadjusted Solution If OAT, RoomT or DAT are such that heat is requiredDiagnostics SOLUTIONIf heat is desired Fault CODEInsufficient OASolution If setpoints are misadjusted SOLUTIONIf less outside air is desired Diagnostics Unit Modes Hotkey Menu SelectionMenu Selection Tree for BACview Menu Selection SET Points HotkeyAlarm History 64 Most Recent Alarm HotkeyResets Hotkey Status Menu HotkeyUser Configurable Output Hotkey Schedules HotkeyClockset Hotkey Help HotkeyFuel Select Hotkey Thermostat Output Curve Ohms Thermistor Output CurveAirflow Station Layout Airflow station layoutZone 583 Controller Specifications Network CommunicationZone 583 Controller Specifications Rnet MRT-Pro or Room Air sensorTypical Wiring Schematic Non-recirculating with evap Dfoa and Dfia model diagramTypical Wiring Schematic Recirculating Dfoa and Dfia model diagrams Recirculating Dfoa and Dfia model diagram Typical Wiring Schematic Trane
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