What It Means
Flame detected while the gas valve is supposed to be off.
American Standard Furnace
American Standard Furnace Error Code 5 Flashes
Troubleshooting guide for the American Standard Furnace system fault 5 Flashes.
ACLogics Fix American Standard code 5 Flashes See how ACLogics handles it → Fix 5 Flashes step-by-step
Possible Causes
- Gas valve stuck open or leaking gas.
- Control board flame sensing circuit malfunction.
Not sure which one it is — or if it's none of these? Try ACLogics today.
Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
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Full Diagnosis
Flame sensed with gas valve off (unexpected flame). This could indicate a gas valve leaking or stuck open, or a control board issue.
All Recorded Causes
Turn off the furnace. Do not continue operation until inspected. Check that the gas valve closes fully. This fault requires a qualified HVAC technician to examine the gas valve and control board.
Verify Before Replacing Parts
- Confirm the exact American Standard model family and furnaces context before acting on a generic code description.
- Walk the entire heating sequence in order instead of jumping straight to the reported code, watching for turn off the furnace.
- Verify each safety device and prove where the sequence stops under live operation, including whether do not continue operation until inspected.
- After the correction, run the system long enough to confirm the furnaces fault does not return under normal load.
Still unsure about this fault?
ACLogics walks you through American Standard Furnace diagnostics step-by-step — so you confirm the cause before swapping parts.
