Lennox ML193UHE furnace 8 red flashes: Rollout Switch Open
Safety issue — act now
What do 8 red LED flashes mean on a Lennox ML193UHE with ignition control 103217-03? The flame-rollout safety switch is open. The control closes the gas valve, and the switch requires a manual reset after a technician identifies and corrects the cause.
This condition involves the gas or combustion side. If you smell gas or a CO alarm sounds: leave, then call your gas utility. Diagnostic info here is reference — combustion repairs are for licensed technicians. All six emergency signs →
Combustion and heat-exchanger diagnosis are technician work. The rollout switch should be reset only by a technician after the cause is found and corrected.
Parts for this code
No model-verified part number is listed here. Have the fault diagnosed and the correct part matched to your furnace before ordering.
Questions about this code
What do 8 red LED flashes mean on a Lennox ML193UHE with ignition control 103217-03?
The flame-rollout safety switch is open. The control closes the gas valve, and the switch requires a manual reset after a technician identifies and corrects the cause.
How do I fix Lennox ML193UHE furnace 8 red flashes?
If you smell gas or a CO alarm sounds, leave the building without operating any electrical switches and call the gas utility or 911 from outside. Without those signs, keep the furnace off, do not reset the rollout switch, and call for service.
How much does it cost to fix Lennox ML193UHE furnace 8 red flashes?
Expect a combustion and heat-exchanger investigation before any reset. Parts and labor depend entirely on what the technician finds as the cause of the rollout.
Applies to
ML193UHE
Different Lennox generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.
Verified against Lennox ML193UHE Installation Instructions, p.39
Verified against Lennox ML193UHE Unit Information / Service Literature, p.9
Verified against Lennox ML193UHE Unit Information / Service Literature, p.12
Last verified 2026-10-07 · page updated 2026-10-07 · how we verify
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