System Diagnosis
Flame problem sensed after ignition (flame instability). This indicates the burner flame itself is abnormal or not sustaining properly.
Troubleshooting guide for the American Standard Furnaces system fault 22 Flashes.
A repeatable stop in the heating sequence at the same safety or prove step.
Weak grounding, marginal flame signal, or venting issues can produce inconsistent code behavior.
ACLogics walks you through American Standard Furnaces diagnostics step-by-step — so you confirm the cause before swapping parts.