Lennox ML193UHE furnace continuous rapid red flashing: Heat Call in Progress
Info — not a fault
What does continuous rapid red flashing mean on a Lennox ML193UHE with ignition control 103217-03? The control is reporting an active heat call and burner operation sequence. Lennox's 103217-03 table does not give exact on/off timing for this flash.
Safe checks before calling
Watch for a pause: uninterrupted rapid flashing is this normal state, while counted flashes followed by a 3-second pause are a fault code.
Questions about this code
What does continuous rapid red flashing mean on a Lennox ML193UHE with ignition control 103217-03?
The control is reporting an active heat call and burner operation sequence. Lennox's 103217-03 table does not give exact on/off timing for this flash.
Does Lennox ML193UHE furnace continuous rapid red flashing mean I need a repair?
No repair is called for by this state alone. If the house is not warming while the LED flashes rapidly, remember this status does not prove the burners are producing heat; book a service visit and note how long it ran.
How much does it cost to fix Lennox ML193UHE furnace continuous rapid red flashing?
A normal heat-call state does not imply any repair bill. Charges arise only if a technician is called to investigate heat that is not reaching the rooms.
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
Last verified 2026-10-07 · page updated 2026-10-07 · how we verify
Related Lennox furnace codes
These codes use the same lennox ml193uhe with ignition control 103217-03 system.