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Lennox G60DF / G60DFV Furnace Codes
Lennox's SureLight service literature also covers boards 100869 (G60UH) and 100870 (G60UHV), which use X + Y flash codes instead; those are the second table on the Lennox document.
| Code | Meaning | What to check |
|---|---|---|
| Both slow flash together | Normal power-on; also shown in cooling and continuous fan. | |
| Both fast flash together | Normal operation: heating demand at the thermostat. | |
| DS1 slow flash, DS2 on | Primary, secondary or rollout limit open. Limits must close within 3 minutes or the unit goes into a 1-hour Watchguard. | Airflow first: filter, blower, closed registers, dirty coil. How to fix → |
| DS1 off, DS2 slow flash | Low pressure switch open, blocked inlet or exhaust vent, or low pressure switch closed before the inducer started. | How to fix → |
| DS1 off, DS2 fast flash | High pressure switch open, blocked inlet or exhaust vent, or high pressure switch closed before the inducer started. | How to fix → |
| Alternating slow flash | Watchguard: burners failed to ignite, limit open over 3 minutes, flame lost 5 times in one heating cycle, or pressure switch opened 5 times in one heating cycle. | How to fix → |
| DS1 slow flash, DS2 off | Flame sensed with the gas valve not energized. | Gas valve leaking through or a shorted flame sense circuit. How to fix → |
| Both on, or one on and one off | Circuit board failure or miswired control. | Check 24 V and 115 V at the board before replacing it. |
| DS1 fast flash, DS2 slow flash | Main power polarity reversed. | Swap line and neutral. |
| DS1 slow flash, DS2 fast flash | Low flame signal (below 0.2 microamps). | Clean or replace the flame sense rod; check ground. How to fix → |
| Alternating fast flash (during ignitor warm-up) | Improper main ground, broken ignitor or open ignitor circuit, or line voltage below 75 V. | How to fix → |
How to read the codes
- Read DS1 and DS2 at the same time; the pair of states is the code. Slow and fast flashes are both normal only when the two LEDs flash together.
- Read the code before cycling power. Watchguard (alternating slow flash) resets itself after an hour, or reset it by removing the thermostat call for a few seconds.
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: Lennox SureLight Ignition System, Two Stage and Two Stage Variable Speed, Service Literature Corp. 0222-L7 (revised 11-2006), Table 5. 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 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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