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The genuine OEM Lennox 34M73 pressure switch ships complete with its factory mounting bracket for a direct, bolt-in replacement. This switch confirms adequate combustion airflow and venting draft before your furnace ignites, closing only when the inducer produces the correct pressure differential and protecting your home from unsafe flue conditions.
Common failure symptoms: A worn 34M73 commonly prevents startup, causes pressure-fault lockouts, produces short-cycling, or leads to repeated failed ignition attempts. Stuck diaphragms, cracked tubing, or a switch that no longer makes contact are the usual causes. The included bracket ensures the assembly is positioned exactly as designed.
Why OEM matters: Lennox calibrates each pressure switch to a specific set point tied to the furnace model and vent layout, and the matched bracket guarantees correct orientation and tubing routing. Generic replacements risk wrong set points and improper mounting, leading to nuisance faults. The 34M73 is the precise OEM assembly your Lennox equipment requires for safe, reliable performance.