OEM Lennox Limit Switch — 25J26

The genuine OEM Lennox 25J26 limit switch is a thermally activated safety device that guards your Lennox furnace against overheating. It senses the temperature in the heat exchanger area and interrupts the burner circuit if conditions exceed the safe operating range, then automatically resets once temperatures return to normal.

When this switch degrades you may experience frequent short cycling, a furnace that locks out on a limit fault, or no heat at all if the contacts fail open. Blocked airflow from a dirty filter can accelerate wear, so it's worth checking airflow whenever the switch trips repeatedly.

Installing the OEM Lennox 25J26 ensures the trip point and reset temperature match your furnace's factory design exactly. A generic switch with the wrong calibration can compromise the safety function or cause nuisance shutdowns — risks that simply aren't worth taking with a component built to protect your heat exchanger. Get dependable, code-correct protection with the factory part. In stock and ships same day before 3PM CST.