The high-pressure function features a fixed 70 PSI differential

and 325-7 Series line pressure regulators

The Honeywell 311852 is technically identical to the 311852/U (universal) model

When diagnosing furnace fan not turning on or intermittent blower issues

Lochinvar & A.O. Smith 100173793 Arm Assembly 324846-701 The high-pressure function features aThe Lochinvar & A. O. Smith 100173793 Arm Assembly is a critical OEM replacement part engineered for high efficiency commercial boilers and heating systems. As a veteran grade gas air arm assembly, this component ensures the precise mechanical alignment necessary for optimal combustion and fluid regulation. Specifically designed for compatibility with Lochinvar Knight series models (including KBN, AWN, and SNA 500), this assembly facilitates the