The furnace shows E9 and locks out; this may occur after repeated failed ignition or flame loss events.

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Intermittent flame sensor signal, weak ignitor, unstable gas supply pressure, dirty burners causing flame lift-off.

Safety: Turn off the power and gas before cleaning or removing burner components.

Steps:

Reset the furnace by turning the power off for 30 seconds and back on. Observe the ignition sequence.
Clean the flame sensor as described in the E4 entry.
Inspect the hot surface ignitor for cracks or white spots; if damaged, replace it with the correct Westinghouse-rated ignitor.
Vacuum burner inlets and crossover ports with a soft brush to remove dust and rust.
If flames light but drop out when the blower starts, a professional should check the gas pressure and combustion air.

Note: Do not repeatedly reset a furnace that continues to lock out; have a technician evaluate the gas train and combustion.

Hard 4/5

Hot Surface Ignitor

Check Price on Amazon

We may earn a commission from links on this page.