This SPNO relay is a versatile industry standard for modernizing older air handlers or replacing failed fan center components

always verify your model and serial number to ensure exact fitment for the collector box assembly

Can this relay replace a 24V or 120V model

a reading significantly different from 15K ohms indicates the resistor is faulty and requires replacement

Reznor 85449 Limit Switch This SPNO relay is aThe Reznor 85449 is a critical safety component designed for precise thermal regulation in commercial gas fired unit heaters and furnaces. This 140 200F Auto Limit Switch monitors internal air temperatures, functioning as a primary high limit safety by interrupting the burner circuit if the heat exchanger surpasses the 200F threshold. As an OEM replacement part, it ensures seamless compatibility with Reznor UDAP, UDAS, and UDX series heaters,