Goodman Furnace 1 Flash — Ignition Failure
A single flash (or continuous flash on some boards) after failed ignition trials usually means the furnace tried to light and never proved flame. Start with a clean flame sensor and a visual ignitor check before assuming the gas valve is dead.
Updated July 2026 · 6 min read · Canada
Symptoms
- Inducer and ignitor sequence, then lockout
- No sustained flame / brief flame then out
- LED shows 1 flash per door chart
Likely causes
- Dirty or oxidized flame sensor
- Cracked hot-surface ignitor
- Low gas pressure or closed gas shutoff
- Failing control board (less common)
What to do
1. Confirm gas is on
Verify the furnace gas cock is parallel to the pipe and other gas appliances still work.
2. Clean the flame sensor
Power off, remove the sensor rod, and polish lightly with fine emery cloth. Re-seat firmly.
3. Inspect the hot-surface ignitor
Look for hairline cracks or a broken element. Do not touch the ceramic with bare fingers if replacing.
4. Retry one ignition cycle
Restore power and call for heat. If it still fails after a clean sensor and intact ignitor, call a tech for gas pressure and board diagnostics.
Stop and call a pro when
- You smell gas
- The ignitor never glows
- Flame lights then drops immediately every cycle after cleaning
Related guides
- Goodman 3 Flashes — Diagnose Goodman (and Amana) furnace LED 3-flash codes: pressure switch, inducer, and flame-sensing failures — plus the parts that usually fix them.
- Rheem 2 Flashes — Rheem and Ruud 2-flash pressure-switch faults: blocked vents, bad hoses, and inducer issues — with the parts that clear most homeowner-accessible failures.
- Lennox E229 — What Lennox communicating alert E229 (flame failure) means, safe flame-sensor cleaning steps, and replacement parts that often clear the alert.
- Goodman 2 Flashes — Diagnose Goodman furnace LED 2-flash codes related to the pressure switch circuit, venting, and inducer operation.
FAQ
Will a dirty filter cause 1 flash?
Rarely. Ignition/flame-sense faults are usually sensor, ignitor, gas, or board related. Still keep the filter clean for overall health.
Need a licensed tech instead?
If the guide says to stop — or the part swap did not clear the fault — get free quotes from licensed local HVAC contractors.
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