Trane furnace — Trane gas furnaces whose integrated control proves flame by rectification, as described in Trane homeowner support for a burner that shuts off after ignition Error Codes Directory

Trane furnace burner lights then shuts off: reading the flame sense fault

When a Trane furnace lights its burner and shuts down a few seconds later, the control has decided it cannot confirm the flame it just created. Trane treats that as a flame sensing condition. The burner did light, so the ignition side worked, and what failed was the proof step that keeps the gas valve open. Applies to: Trane gas furnaces whose integrated control proves flame by rectification, as described in Trane homeowner support for a burner that shuts off after ignition Trane support describes this behaviour for gas furnaces whose control proves flame by passing a small current through it. Trane also sells equipment where the same symptom has a different cause, and any numeric or flash code shown on your control is read from that model's own literature rather than from this description. Owner-safe checks: Listen to a complete heating call and note whether the burner lights at all, and how many seconds it stays alight. | Count how many calls succeed and how many fail over two or three days, including the time of day for each. | Replace a loaded filter with the specified clean one, since restricted airflow produces a different fault that can be confused with this one. Qualified technician: Measuring the flame signal in microamps, cleaning or repositioning a sensing electrode, and testing the ground path are licensed gas-furnace tasks. | Do not attempt to clean a sensing rod yourself. It sits in the burner compartment beside live components and a gas train, and an abrasive left on the surface makes the fault worse.