HVAC Code Lookup

American Standard fault codes

28 documented codes for American Standard furnaces, each cited to the manufacturer's own manual. American Standard Heating and Air Conditioning is a Trane Technologies brand and shares furnace platforms and integrated furnace control (IFC) boards with Trane. Older Silver/Gold 80 and 95 furnaces (*UD1/*DD1, CUB1/CDB1) use a single red diagnostic LED that blinks a count; current models (A801X, A951X, S8V2, S9V2 and the Silver/Gold/Platinum 80 and 95 lines) use a seven-segment display showing E-codes. Wording differs slightly from the Trane version of the same table - for example American Standard prints '4 Flashes --- Open Temperature Limit Circuit' where Trane prints 'Open High Limit Device'..

Furnace codes

CodeMeaningSeverity
Flashing SlowRed LED flashing slowly and steadilyNormal standbyStatus
Flashing FastRed LED flashing rapidly and steadilyNormal operation with an active call for heatStatus
Continuous ONLED on solid, never blinkingThe integrated furnace controlHard lockout
Continuous OFFLED completely darkThe control board is not receiving powerWarning
2 Flashes2 flashes, pause, repeatSystem lockoutHard lockout
3 Flashes3 flashes, pause, repeatDraft pressure errorSoft lockout
4 Flashes4 flashes, pause, repeatOpen temperature limit circuitSoft lockout
5 Flashes5 flashes, pause, repeatFlame is being detected when there should be no flame presentSafety fault
6 Flashes6 flashes, pause, repeatThe 115 volt AC line and neutral are reversed at the furnace, the furnace is poorly grounded, or supply voltage is too lowWarning
7 Flashes7 flashes, pause, repeatGas valve circuit errorSafety fault
8 Flashes8 flashes, pause, repeatLow flame sense signalWarning
9 Flashes9 flashes, pause, repeatThe control is directing the technician to check the igniter circuit and the voltage between line neutral and 24VAC common, which points at an igniter or grounding problemWarning
E01Internal integrated furnace control failureHard lockout
E2.1Retry exceededHard lockout
E2.2Recycles exceededHard lockout
E2.3The control commanded the gas valve on and the valve did not energize, ten times in a rowHard lockout
E3.1The pressure switch is reading closed when the control expects it to be open, which the control calls a shorted pressure switchSoft lockout
E3.2The pressure switch will not close, so the control cannot prove the draft inducer is moving flue gas and will not open the gas valveSoft lockout
E04A safety limit has opened: the main thermal limit, a flame rollout switch, or the reverse airflow switchSafety fault
E05The control is sensing a flame when there should not be one - for example with the gas valve commanded offSafety fault
E6.1Line and neutral are reversed in the 115 volt supply to the furnaceWarning
E6.2The furnace does not have a good electrical ground, which the control needs in order to sense flame reliablyWarning
E6.3Igniter faultHard lockout
E7.1The gas valve is energized when the control has commanded it offSafety fault
E08The flame current the control reads is low but still high enough to keep runningWarning
E09The inducer limit switch or the condensate pressure switch is openSoft lockout
E11Gas valve relay faultSafety fault
E12The fuse on the integrated furnace control has opened, so 24 volt control power is lostHard lockout

Looking it up by flash count?

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Manuals used for this page