Lennox ML193UHE furnace 13 red flashes: Low Line Voltage
Professional repair
What do 13 red LED flashes mean on a Lennox ML193UHE with ignition control 103217-03? The ignition control is reporting low line voltage on the furnace's power supply. The code identifies a supply condition, not a specific failed part in the furnace.
Before you touch anything: the six signs that mean stop troubleshooting and call a pro →
Measuring line voltage and tracing a supply problem require live electrical testing. That belongs to a licensed technician or electrician, not the homeowner.
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 13 red LED flashes mean on a Lennox ML193UHE with ignition control 103217-03?
The ignition control is reporting low line voltage on the furnace's power supply. The code identifies a supply condition, not a specific failed part in the furnace.
How do I fix Lennox ML193UHE furnace 13 red flashes?
Arrange electrical diagnosis and mention whether lights dim or other appliances act up when the furnace starts. A technician measures the supply under load and finds whether the drop is in the furnace circuit or the building's service.
How much does it cost to fix Lennox ML193UHE furnace 13 red flashes?
Cost depends on where the voltage drop originates. A connection problem on the furnace circuit and a utility or service-entrance issue involve different repairs and responsible parties.
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.