by measuring the differential pressure across a filter bank

Mars 43350

Why is the board showing a 3-flash red code

" or if you observe erratic continuity during bench testing

This SPST cooling thermostat is the direct field replacement for the legacy 803 model

Lennox 74W55 Blower Assembly 321702-401 by measuring the differential pressureThe Lennox 74W55 Combustion Blower Assembly is a high performance draft inducer specifically designed for modern high efficiency furnaces. Also referenced under part numbers 74W5501 and LB 94724AA, this assembly is a critical component for maintaining the correct fuel to air ratio during the combustion cycle. Operating at 120 Volts and 60 Hz, this 1 40 HP motor delivers 3250 RPM to effectively pull flue gases through the heat exchanger, ensuring safe