including the FX

preventing hazardous leaks and maintaining AEO-ranked energy efficiency

it ensures precise calibration and seated integrity

provided the system is configured correctly for the fuel type

It is not designed for use with Hytrel or Urethane sleeves

Lennox 34M73 Pressure Switch 321702-401 including the FXThe Lennox 34M73 Pressure Switch is a critical safety component designed for precise furnace draft inducer monitoring in residential and commercial heating systems. This OEM Lennox replacement part is factory calibrated to a . 22"wc set point, ensuring the exhaust vent maintains adequate negative pressure before allowing the ignition sequence to proceed. Featuring a Single Pole Single Throw (SPST) configuration and a standard 1 4" barb connection,