OEM Lennox Flame Rollout Switch — 31J96

The genuine OEM Lennox 31J96 flame rollout switch is a thermally activated safety limit switch that guards against dangerous flame rollout in your Lennox furnace. Mounted near the burner assembly, it senses abnormal heat caused by flames escaping the heat exchanger — often the result of a blocked flue, cracked heat exchanger, or poor combustion — and immediately shuts down the furnace to prevent damage or fire.

Common failure symptoms: A tripped or failed 31J96 typically causes the furnace to stop heating, lock out after a short run, or refuse to ignite at all. A switch that has opened due to a genuine fault will not reset until the underlying cause is corrected, while a defective switch may trip nuisance shutdowns even when combustion is normal.

Why OEM matters: Flame rollout switches are calibrated to trip at a precise temperature threshold. An incorrect or off-spec switch can fail to protect the equipment — or trip prematurely and leave you without heat. The factory 31J96 is built to Lennox's exact temperature rating and mounting specification, ensuring dependable safety response and warranty compliance. For a life-safety device, only genuine OEM will do.