Trane / American Standard · Furnace error code

5 flashesFlame sensed with no gas valve signal

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Stop: this involves gas or the sealed refrigerant system.

OnCall Tech only describes the symptom. Gas work needs a licensed gas technician, and refrigerant work requires EPA Section 608 certification. If you smell gas: shut off the supply if it is safe, do not switch anything on or off, ventilate, leave the building and call the gas utility.

OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

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