Heating and water heater fault codes

Choose your equipment. Each table shows only codes confirmed in a manufacturer document, states which models that document covers, and links to it. If you are unsure what your light means, start with how to read furnace blinking light codes or use the decoder.

Gas furnace

Carrier / Bryant

Carrier and Bryant furnace status codes (5 furnace manuals compared)

16 codes

Trane / American Standard

Trane furnace error codes: blinking lights and S9V2 / S9X display codes

38 codes

Goodman / Amana

Goodman and Amana 96% furnace alarm codes

37 codes

Lennox

Lennox furnace diagnostic codes (SL280DFV)

36 codes

Rheem / Ruud

Rheem and Ruud furnace fault codes (801T series)

17 codes

York

York TM9V furnace flash codes

19 codes

Tankless water heater

Rinnai

Rinnai tankless water heater diagnostic codes

40 codes

Rheem

Rheem tankless water heater error codes

34 codes

Navien

Navien NPN tankless water heater error codes

19 codes

Takagi

Takagi tankless error codes (T-KJr2, T-K4, T-D2)

14 codes

Noritz

Noritz tankless error codes

7 codes

Commercial gas water heater

Bradford White

Bradford White D-series (24 V Honeywell / ICON HD) error codes

19 codes

Ductless mini-split

Mitsubishi Electric

Mitsubishi Electric mini-split error codes

18 codes

Daikin

Daikin mini-split error codes: FTXC, FTX-B, AXVJU and FTX-N/U series

37 codes

Mitsubishi

Mitsubishi MSZ/MSY-GL blinking light codes

8 codes

Fujitsu

Fujitsu wall-mounted mini-split error codes

32 codes

Boiler

Weil-McLain

Weil-McLain Ultra boiler lockout codes

30 codes

Not seeing your brand? We add brands only after we have read the manufacturer's own code table. Check your owner's manual or the label on your equipment. Honest coverage beats a long list of guesses.