American Dryer Error Code FLAME FAULT: Flame Lost After Lighting

What does American Dryer (ADC) FLAME FAULT mean?

After the Phase 7 control lights the burner, it keeps watching for proof of flame through a flame sensor. During the trial for ignition the sensor sees the flame and the cycle goes on. FLAME FAULT describes a different story: the flame was there at first and then went away. The control does not give up at once. It makes five retries, and only when the flame still cannot be held does it stop and show the message. What operators see is heat that starts, then drops out, and a dryer that finishes the load cold. A dryer that starts hot and then goes cold is the classic pattern. The manual lists a flame sensor or its wire that loses the signal, gas pressure or burner airflow that lets the flame drop out, an exhaust restriction that disturbs the flame, and a gas valve that closes after the flame lights. Some of those are about the sensor reporting wrongly and some are about a real flame that cannot stay lit, which is why the diagnosis takes measurement of both the gas side and the airflow.

Affected models and control systems

This applies to gas American Dryer tumblers with the Phase 7 OPL microprocessor controller, such as the AD-115 and AD-170, and the Phase 6 control on ML-175 and ML-190 models. Other controller generations use different messages.

Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.

What you may notice

• Heat starts and then drops out within the cycle
• The burner clicks and relights several times in a row
• The load ends damp and cool

Possible causes

Listed in American Dryer (ADC)'s documentation

• A flame sensor or its wire that loses the signal
• Gas pressure or burner airflow that lets the flame drop out
• An exhaust restriction that disturbs the flame
• A gas valve that closes after the flame lights

Other likely causes — what usually sits behind FLAME FAULT on this control. A technician confirms which one it is before any part is replaced.

• A flame sensor coated with residue so it loses the signal when the flame is steady
• Low incoming gas pressure on a shared line when several machines run at once
• An exhaust restriction that pushes back on the burner and lifts the flame off its ports

Safe checks before calling for service

How a technician diagnoses FLAME FAULT

1. Read the message and watch a heat call to see when the flame is lost.
2. Check the flame sensor signal and clean or test the sensor and its wire.
3. Measure gas pressure at the valve with the burner lit.
4. Check exhaust and burner airflow for restriction.
5. Test whether the gas valve holds open once the flame proves.

How FLAME FAULT differs from similar codes

BURNER IGNITION CONTROL FAULT on the same control is different: no valve signal came at all, while here the flame did appear and was then lost.

Technical reference

Document

AD-115/120/170 ML-120/130/145/170 Service Manual, Phase 7 Microprocessor Controls (part 451102 R2), Diagnostic messages pp.43-44

Maker documentation

American Dryer (ADC) owner support

Edition

Part 451102 R2

Models / control

Phase 7 OPL microprocessor controller (also Phase 6 on ML-175/190)

Section

Diagnostic messages pp.43-44

Checked

October 2026

We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.