Goodman furnace 1 red flash: Flame sensed when no flame should be present
One red flash means the control is detecting flame while the gas valve should be closed. Either gas is burning when it should not be, or the sensing circuit is reporting a flame that is not there.
Applies to: Goodman GMEC96 and Amana AMEC96 two-stage gas furnaces, which use a three-colour diagnostic LED. Red always indicates a fault. Green indicates cooling or standby. Amber is mostly heating status but not exclusively — rapid amber is a low flame sense warning, and three and four amber flashes are thermostat wiring faults. The colour must be read along with the count.
What it means
The GMEC96 control uses colour as well as flash count, and red is reserved for faults. One red flash means flame was proved at a moment when the gas valve was commanded shut. This is treated as serious because one of the two possible causes is a gas valve that is not closing fully — gas entering the combustion chamber outside a controlled cycle. The other cause is electrical: a short in the flame sensor wiring produces a signal the control cannot tell apart from a real flame. Since it cannot distinguish them, it assumes the dangerous one, which is correct behaviour for a control managing a gas appliance.
Most common causes
- A gas valve leaking through or not closing fully, leaving a small flame after the cycle ends.
- A slow-closing gas valve, where flame lingers briefly after shutdown.
- A short to ground in the flame sensor wiring or at the sensor itself.
- A chafed or damaged sensor wire touching the cabinet.
- A failed control board misreading the flame signal.
- Residual flame on a burner after the main flame is cut.
How to diagnose it
- Confirm the colour is red and not amber. One amber flash on this control is normal first-stage heating, which is the opposite of a fault.
- Note whether the inducer runs continuously without the furnace heating, which is the control purging the heat exchanger.
- Do not open the burner compartment while the furnace is powered.
- Note any smell of gas — if there is one, act on the fix below immediately rather than continuing to diagnose.
How to fix it
- If you smell gas: leave the building, operate no electrical switches, and call your gas utility's emergency line or the fire service from outside. Do not return to investigate.
- With no gas smell, switch the furnace off at its service switch and leave it off until a licensed technician has seen it.
- This is entirely technician work, involving the gas valve and the flame-sensing circuit.
- Do not reset repeatedly to see whether it clears. If a valve is passing gas, each reset is another opportunity for it to accumulate.
Notes
On this control the colour carries as much information as the count. One flash means a fault in red, normal first-stage heating in amber, and normal low-stage cooling in green — three completely different situations sharing one count.
Related
- 10 red flashes — Gas flow detected with a call for heat
- 1 amber flash — Normal operation — first stage heat
All codes for this manufacturer
Goodman and Amana furnace fault codes — every code, with what differs between models.
Not sure this is your brand?
The same count means something else on other furnaces. What 1 flash means on every brand puts them side by side.
Models this code appears on
From the manufacturer's per-model database. If your model is not listed, this code may not exist on your board, or it may mean something different — check the model page.
The same fault on other control families
Flame detected when the gas valve should be closed is a fault every board takes seriously, and it appears across brands under different numbers: York's one red flash is this board's near-twin — the two code tables share a control lineage — while Carrier logs it as code 22, abnormal flame-proving signal and Lennox as alert 241. The site's flame sensor code hub tracks twenty-two codes for this fault class across eleven control families, which says something about how universally controls are built to catch it.
What the fix costs
The two possible culprits carry very different bills. If flame is genuinely present when it should not be, the gas valve is failing to close fully — gas valve replacement runs $300–900 per the repair cost guide, which notes flatly that it is never a DIY part. If the sensing circuit is reporting a flame that is not there, the fix may be as small as addressing the sensor or its wiring. Only a technician can tell which furnace you have, so the honest budget is the $75–150 diagnostic first, with the valve range held in reserve rather than assumed.
DIY or call a pro?
There is no DIY branch on this code. A valve that lets gas through when the control has ordered it shut is the kind of fault safety systems exist for, and resetting the furnace to see if the code clears means re-running a gas sequence the control has already flagged. If you ever hear burners running when the thermostat is not calling, or smell gas, close the appliance gas shutoff and make the call an urgent one. Otherwise leave the furnace off and book a technician promptly — this is a same-week repair, not a watch-and-wait code.
What this looks like
From the outside, this usually shows up as the furnace turns over but never lights — that walkthrough covers what to check in order, and when it stops being a homeowner job.
Sources
- Goodman Manufacturing — Diagnostic Code Identification System (model-specific fault code lookup)
- Goodman Technical Services Service Bulletin SF-042 — Gas Valve Diagnostics