OEM Lennox High Pressure Switch — 86M36

The genuine OEM Lennox 86M36 high pressure switch is a refrigerant-side safety control that protects your Lennox condensing unit from dangerously high discharge pressure. Wired into the control circuit, it opens and shuts down the compressor when head pressure climbs too high — commonly from a dirty condenser coil, a failing condenser fan, or a system overcharge — preventing catastrophic compressor damage.

Common failure symptoms: A faulty 86M36 may trip nuisance shutdowns even when pressures are normal, fail to reset, or stick closed and offer no protection at all. Symptoms include a compressor that won't start, cooling that cuts out under load on hot days, or a unit that locks out and requires a manual reset.

Why OEM matters: Pressure switches are calibrated to specific cut-out and cut-in PSI values, and those setpoints must match your Lennox system's refrigerant and design pressures. A generic switch with the wrong thresholds either shuts the unit down needlessly or lets pressure rise to a level that destroys the compressor. The OEM Lennox 86M36 is set to factory specification with the correct fitting and connection, delivering reliable protection and a proper fit for your equipment.