this assembly ensures precise ignition timing and operational safety for Reznor unit heaters

Operating on a standard 120V AC ignition system

As a professional-grade single point connection kit

208-230V specifications

and gas applications where high-cycle performance is non-negotiable

Lennox 21N39 Scale Insert 318973-401 this assembly ensures precise ignitionMaintain peak performance in humidification systems with the Lennox 21N39, a precision engineered scale control insert designed to manage mineral accumulation and ensure consistent evaporation rates. This OEM humidifier replacement part acts as the structural frame and pad holder for high capacity systems, effectively channeling water across the media while trapping scale before it can compromise internal components. Measuring 14 3 8" by 10", this