Goodman / Amana / Daikin furnace — 7 LED flashes: flame not proven / flame-sense fault
Reported Symptom
Burners light but shut off after a few seconds, then retry. LED flashes seven times. May end in lockout after repeated failures.
Safety Warnings
- •Combustion and carbon-monoxide hazard: shut off gas and ventilate if you smell gas. Inspect the heat exchanger and flue for cracks or leaks before returning the unit to service — a CO leak can be fatal.
- •Turn off power at the furnace disconnect/breaker before opening the control or blower compartment. Verify zero voltage before touching line-voltage terminals.
- •Never bypass or jumper the limit, rollout, or pressure switches — they are life-safety controls. Resetting a lockout only clears the latch; a unit that re-locks has a live fault that must be corrected.
- •Follow all manufacturer service procedures and applicable codes. If the fault is outside your training, escalate to a qualified technician.
Possible Causes
- 1Dirty/oxidized flame sensor rod
- 2Flame sensor cracked or grounded
- 3Poor furnace ground (rectification needs a good ground)
- 4Low flame-sense microamps
- 5Reversed line polarity
Tools Required
- Multimeter (microamp/DC µA capable)
- Insulated screwdriver set
- Fine abrasive pad
- Flashlight
Parts Required
- Flame sensor
Diagnostic Steps
Confirm burners light and a visible flame envelops the sensor rod before shutoff.
Expected: Flame contacts the rod.
If fails: If flame is weak/not reaching the rod, correct gas/burner issue first.
De-energize; clean the flame rod with a fine abrasive pad (not sandpaper grit that leaves residue).
Expected: Clean, bright rod.
If fails: —
Place the meter in series on the flame-sense lead and read microamps during flame.
Expected: Microamps above the board’s minimum (commonly ~1.5–4 µA, per label).
If fails: Below minimum → replace flame sensor; re-check ground and polarity.
Verify furnace ground and line polarity are correct.
Expected: Good ground; correct polarity.
If fails: Repair ground / correct polarity (see polarity guide).
Solution
Clean or replace the flame sensor and confirm flame-rectification microamps exceed the board minimum. Because rectification is ground-referenced, also verify a solid equipment ground and correct line polarity. The 7-flash fault clears once the board reliably proves flame.