Once the original seal is compressed and heat-cycled

Quick Identification: Features a high-visibility orange jacket and clear labeling to streamline diagnostic and replacement workflows

Optimized Combustion: Precision-balanced fan wheel ensures stable airflow and prevents "Ignition Failure" or "Blower Prover" fault codes

the mounting holes and drain ports will not align

meaning it initiates the spark and gas valve energization immediately upon receiving a call for heat

Lennox 11U72 Pressure Switch 340155-7026 Once the original seal isThe Lennox 11U72 Pressure Switch is a critical safety component designed for precise combustion air monitoring in high efficiency gas furnaces. As a genuine OEM replacement part (also identified as Lennox 104371 09), this single pole, single throw (SPST) switch features a normally open contact configuration. It is factory calibrated to actuate at a 0. 90" WC (inches water column) set point, ensuring the draft inducer motor is generating sufficient