Trane Furnace Error Code 8 Flash: How to Fix It

Q: What causes Trane furnace error code 8 flash?

Error code 8 flash is caused by a low flame sense signal, typically from a dirty or corroded flame sensor that can't properly detect the flame. Other causes include a failing igniter, gas pressure issues, or debris in the burner area.

Q: How often should I clean my Trane furnace flame sensor?

Clean the flame sensor annually as part of regular furnace maintenance. If you experience frequent shutdowns or error codes, you may need to clean it more often, especially in dusty environments.

Q: Can I use sandpaper to clean the flame sensor?

No, never use sandpaper on the flame sensor. Use only fine steel wool or emery cloth to gently clean the metal rod. Sandpaper is too abrasive and can damage the sensor's surface, affecting its ability to sense flames.

Q: Why does my Trane furnace keep showing 8 flash after cleaning?

If the error persists after cleaning, the flame sensor may be permanently damaged and need replacement, or there could be issues with the igniter, gas pressure, or wiring connections that require professional diagnosis.

Q: Is it safe to reset my Trane furnace when it shows 8 flash?

You can try resetting the furnace once by turning it off for 5 minutes then back on, but if the 8 flash error returns, address the underlying cause rather than repeatedly resetting. The error is a safety feature preventing unsafe operation.

Abstract

Trane furnace error code 8 flash indicates a low flame sense signal, typically caused by a dirty flame sensor or weak ignition. This error prevents your furnace from operating safely and requires cleaning the flame sensor or addressing ignition issues to restore proper heating.