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Rheem / Ruud 801V Ultra Low NOx Furnace Codes
Ultra Low NOx furnaces have an ignition pressure switch, a venturi air inlet switch and a gas inlet pressure switch that standard furnaces don't, so several codes here exist only on this series. Rheem's contractor app gives more detail per code (scan the QR code on the furnace).
| Code | Meaning | What to check |
|---|---|---|
| CL | Inducer speed calibration running. | Normal operation, not a fault. |
| 10 | 1 hour lockout. | How to fix → |
| 11 | Failed ignition. | How to fix → |
| 12 | Low flame sense. | How to fix → |
| 13 | Flame lost. | How to fix → |
| 14 | Unexpected flame. | Gas valve leaking through or a shorted flame sense circuit. How to fix → |
| 22 | Main / aux limit open. | How to fix → |
| 26 | L1 and neutral reversed. | Swap line and neutral. |
| 33 | Rollout switch open. | How to fix → |
| 34 | Induced draft motor overcurrent. | How to fix → |
| 42 | Flame LED not detected. | |
| 43 | Ignition pressure switch closed when it should be open. | How to fix → |
| 55 | Combustion pressure switch closed when it should be open. | How to fix → |
| 56 | Ignition pressure switch open when it should be closed. | How to fix → |
| 57 | Combustion pressure switch open when it should be closed. | How to fix → |
| 58 | Water sensor jumper not attached. | |
| 61 | Blower fault. | |
| 71 | Inducer fault. | How to fix → |
| 74 | Gas inlet pressure switch open. | How to fix → |
| 75 | Venturi air inlet pressure switch open. | |
| 93 | Control fault. |
How to read the codes
- 0 means standby with no faults. H gas heat, F call for continuous fan, CL inducer speed calibration running.
- Two-digit codes show the first digit for one second, then the second for one second, then a half-second pause. Each fault shows at least twice, even if it has already cleared.
- Two faults alternate, with the top segment of the display lit for half a second between them. Four failed ignitions or five flame losses in a row cause a one-hour lockout (10 alternates with 11 or 13). An unexpected flame lockout shows 14 with 10.
- If the main limit has been open more than 150 seconds during a heat call, the control declares a dead blower: 61 alternates with 22 until the limit closes, then 61 with 10 during the lockout. The fourth time in one heat call is a hard lockout.
Codes point to a circuit, not a part. Test before replacing anything, and never jumper a limit, rollout or pressure switch to keep a furnace running. Gas and line-voltage work is for trained technicians.
Source: Rheem Installation Instructions, 80+ communicating upflow/horizontal Ultra Low NOx gas furnaces with constant CFM/PWM blower, 92-24161-184-04, Fault Codes, p. 42. The "meaning" column follows the manufacturer's wording; "what to check" is our field summary. Always go by the label on the furnace you're working on.
Related
- How to read furnace LED flash codes
- Furnace pressure switch troubleshooting
- Flame sensor microamps and cleaning
Other brands
- Lennox Merit ML180UH (80% single-stage)
- Carrier 58CVA / 58CVX (80% variable-speed two-stage)
- Rheem / Ruud R96V / 96MDV (96% two-stage communicating)
- Goodman / Amana GR9S80 / GD9S80 (80% single-stage)
- Trane / American Standard S9X1 / S9X2 / S9B1 (96% condensing)
- Lennox SL280UHV (80% two-stage variable speed)
- Goodman / Amana / Daikin GM9S96 / GC9S96 / GM9S92 (96% and 92% condensing, single-stage)
- Carrier 59TP6C two-stage condensing with InteliSense (Performance series)
- Lennox G60DF / G60DFV (older two-stage SureLight boards 18M3401, 46M9901, 18M9901, 49M5901)
- Lennox G60UH / G60UHV (SureLight boards 100869 and 100870)
- Rheem / Ruud R801T Ultra Low NOx (14 ng/J) single-stage upflow/horizontal, constant-torque blower
- Rheem / Ruud 802V / 80MDV (80% two-stage communicating, ECM blower; model numbers (-)802V and (-)(-)80MDV)
- Trane / American Standard S8B1 / S8X1 / S8X2 (80% single-stage and two-stage)
- Goodman / Amana GMVC96 / GCVC96 (96% two-stage variable-speed, *MVC96*BA and *CVC96*BA)
- Goodman / Amana GMVS96 / AMVS96 U-revision (96% variable-speed with analog pressure sensor, model numbers GMVS96*U and AMVS96*U)
- Goodman / Amana GMVM96 / GCVM96 / AMVM96 / ACVM96 (96% modulating, model numbers *MVM96 and *CVM96)
- Rheem / Ruud R801T / 80MSX (80% single-stage, constant-torque blower; model numbers (-)801T and (-)(-)80MSX)
- Rheem / Ruud 802P / 80MDP (80% two-stage, model numbers (-)802P and (-)(-)80MDP)
- Rheem / Ruud 802T / 80MDT (80% two-stage with constant-torque blower, model numbers (-)802T and (-)(-)80MDT)
- Rheem / Ruud 801S / 801P / 80MSS / 80MSP (80% single-stage, model numbers (-)801S, (-)801P, (-)(-)80MSS and (-)(-)80MSP)
- Carrier 58STA / 58STX (80% single-stage, 4-way multipoise)
- Carrier 58SB0A / 58SB1A (single-stage, non-condensing)
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