Trane Direct-Fired Indoor and Outdoor Make-Up Air Units, MUA-SVP01A-EN Fault Code Unit off/Fan on

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Diagnostics

FAULT CODE: Unit off/Fan on

PROBLEM: The controller has not activated the unit enable output to start the fan, but the fan status input, is receiving a signal that the fan is running. This fault will automatically clear about 15 seconds after the fault is corrected.

SOLUTION: If fan is running

1.Is controller unit enable output LED for lit?

–Yes. There is a problem with the controller program. Call factory.

–No. Continue.

2.Is controller output contact for the unit enable output closed?

–Yes. Turn off the power to the controller and recheck. If contact is still closed the controller output is shorted. Replace the controller.

–No. Continue.

3.Is the unit enable relay energized?

–Yes. There is a short or jumper in the wiring. Determine cause and rectify.

–No. Continue.

4.Is motor starter energized?

–Yes. There is a short or jumper in the wiring. Determine cause and rectify.

–No. Continue.

5.Is the fan status relay energized?

–Yes. There is a short or jumper in the wiring. Determine cause and rectify.

–No. Continue.

6.Is the fan status relay's normally open contact, closed?

–Yes. Replace relay.

–No. Continue.

7.Is there continuity between at the controller between the fan status terminals?

–Yes. There is a short in the wiring between these terminals. Determine cause and rectify.

–No. Replace controller.

SOLUTION: If fan is not running

1.Is the fan status relay's normally open contact, closed?

–Yes. Replace relay.

–No. Continue.

2.Is there approximately 5VDC at both controller terminals used for the fan status?

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

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Contents January Controls Programming GuideOverview Networking Direct-Fired Indoor and Outdoor Units MUA-SVP01A-EN Contents Contents MDT Controls Unit Operating ModesMRT-Pro Controls MRT ControlsUnit Operating Modes MRT-Expert Controls Unit Operating Modes Heating Mode Heating/Ventilating/Cooling Operating ModesGeneral Burner Control Unit Operating Modes Ventilation Mode M P E R a T U R E S E Cooling ModeDamper Control Modes Manual ModeMixed Air Temperature Mode Building Pressure Mode 100% Outside Air FunctionsMinimum Ventilation FreezestatDirect Acting User Configured PID Control85ºF Direct acting Reverse ActingReverse acting Multiplexed Inputs Unit ResetsClock Set Diagnostics Critical Fault CodesFault Code Low Discharge Temperature Diagnostics Direct-Fired Indoor and Outdoor Units MUA-SVP01A-EN Fault Code Safety Circuit Open SOLUTIONIf fan is running check prior alarm log Fault CODEBurner StatusFault Code Burner Hand Fault Code Flame Failure Diagnostics Non-Critical Fault CodesFault Code Unit off/Fan on Solution If fan is runningSolution If fan is not running Fault CODEUnit on/Fan off SOLUTIONIf fan/motor is runningSolution If fan/motor is not running Fault Code Check Airflow Switches SOLUTIONIf clogged filter switch is closing Fault Code Clogged Filter SwitchSOLUTIONIf setpoints are misadjusted Fault CODEEnergy Save ModeSolution If OAT, RoomT or DAT are such that heat is required SOLUTIONIf setpoints are not misadjustedDiagnostics Fault CODEInsufficient OA Solution If setpoints are misadjustedSOLUTIONIf heat is desired SOLUTIONIf less outside air is desired Diagnostics Menu Selection Menu Selection Tree for BACviewUnit Modes Hotkey SET Points Hotkey Menu SelectionResets Hotkey Alarm HotkeyAlarm History 64 Most Recent Status Menu HotkeySchedules Hotkey User Configurable Output HotkeyHelp Hotkey Clockset HotkeyFuel Select Hotkey Ohms Thermistor Output Curve Thermostat Output CurveAirflow station layout Airflow Station LayoutNetwork Communication Zone 583 Controller SpecificationsRnet MRT-Pro or Room Air sensor Zone 583 Controller SpecificationsNon-recirculating with evap Dfoa and Dfia model diagram Typical Wiring SchematicTypical Wiring Schematic Recirculating Dfoa and Dfia model diagrams Recirculating Dfoa and Dfia model diagram Typical Wiring Schematic Trane