Furnace won't light: igniter glows, no flame

The inducer runs, the igniter glows orange, and then nothing happens. After three or four attempts the furnace locks out. The codes below are how each manufacturer reports it.

What is actually happening

In a normal heating sequence the control starts the inducer, waits for the pressure switch to prove draft, energises the hot surface igniter for a warm-up period of around 15 to 45 seconds, then opens the gas valve. If the igniter glows and no flame follows, everything up to the gas valve worked. The failure is at the gas, at the valve, or at flame proving.

What causes it

The usual causes are no gas reaching the burners — a closed manual valve, an interrupted supply, or a gas line that was worked on recently — a gas valve that is not being energised or has failed, or an igniter that glows but has drifted out of position and is not close enough to light the gas. If the igniter never glows at all, the fault is different again: an open igniter, a control not energising it, or on several brands a bad chassis ground or reversed line voltage, which Goodman, Trane and York all report in the same code as an igniter fault.

The codes that report this

22 codes across 10 control families. Each links to what that manufacturer says about it.

Brand	Code	What it reports
Armstrong	3 flashes	Burner failed to light, or lost flame during a heat demand
Armstrong	5 flashes	Watchguard — burner failed to light, retries or recycles exceeded
Carrier	Status code 14	Ignition lockout
Goodman	1 flash	Lockout after too many failed ignition attempts
Goodman	8 flashes	Igniter circuit fault, most often caused by poor grounding
Goodman	rapid flashing	Reversed 115 volt polarity, a grounding problem, or an open igniter circuit
Goodman	E0	Lockout after too many failed ignition attempts
Goodman	E7	Igniter fault or improper grounding
Goodman	12 red flashes	Ignitor relay failure
Heil	6 + 1 flashes	Soft lockout — failed to light within four trials for ignition
Lennox	Alert code 207	Hot surface igniter sensed open
Lennox	Alert code 270	Flame failed to ignite — Watchguard
Lennox	Alert code 273	Flame failed in run mode — Watchguard
Lennox	Alert code 275	Flame out of sequence — Watchguard
Lennox	Alert code 290	Ignition circuit fault — Watchguard
Lennox	Alert code 291	Heating airflow below minimum — Watchguard
Lennox	Alert code 292	Indoor blower motor will not start — Watchguard
Lennox	Alert code 294	Inducer motor overcurrent — Watchguard
Rheem	4 blinks	Lockout after five failed ignition attempts
Trane	9 flashes	Ignitor circuit problem, or low voltage between neutral and 24 volt common
York	12 red flashes	Open hot surface igniter
York	7 red flashes	One hour lockout after ignition retries

Worth knowing

Most controls allow a fixed number of attempts, normally three, then lock out for about an hour before retrying. That is why a furnace with this fault often appears to work for one cycle and then quit — it is not recovering, it is retrying on a timer.

Other symptoms

This site is a reference, not a substitute for a licensed HVAC technician. Gas appliances can leak carbon monoxide and cause fire. Anything involving gas lines, the heat exchanger, or the flame sensing circuit should be handled by a licensed professional. Pages are written with AI assistance from the sources listed on each page and checked against them before publishing.