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Rheem / Ruud 802T / 80MDT Furnace Codes
The (-) in the model number stands for the brand prefix (Rheem or Ruud). The code list matches the 802P / 80MDP; the communicating 802V / 80MDV uses a longer list with its own chart.
| Code | Meaning | What to check |
|---|---|---|
| 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 → |
| 20 | Twinning fault. | |
| 22 | Main limit open. | How to fix → |
| 26 | Line and neutral reversed. | Swap line and neutral. |
| 33 | MRLC (manual reset limit control, also called rollout) open. | How to fix → |
| 44 | Low pressure switch closed. | How to fix → |
| 45 | Low pressure switch open, inducer on high speed. | How to fix → |
| 46 | Low pressure switch open, inducer on low speed. | How to fix → |
| 55 | High pressure switch closed. | How to fix → |
| 57 | High pressure switch open. | How to fix → |
| 61 | Blower fault: blower unable to run. | Declared when the main limit has been open more than 150 seconds. After four of these in one heat call the control goes into hard lockout, which can be reset by cycling the heat call. |
| 93 | Hard lockout: internal control fault, or voltage sensed on the gas valve contacts when it should not be (welded relay). | Cannot be reset by cycling the heat call. Not in the main code table; described in the manual's lockout section. |
How to read the codes
- 0 means standby with no faults. Letters show the current call: C compressor on (cooling or heat-pump heat), H high gas heat, h low gas heat, F continuous fan.
- 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.
- Lockouts clear once the original fault is fixed and power is cycled. A soft lockout also clears if the heat call is turned off for more than 2 seconds but less than 20. If the low pressure switch does not close within 60 seconds of inducer operation, the control waits in a five-minute lockout and then retries by itself.
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, (-)802T / (-)(-)80MDT upflow/horizontal two-stage gas furnaces, 92-24161-167-00, Diagnostics and Fault Codes, pp. 40-41. 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 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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