Precise Calibration: Factory-set at -1

McDonnell & Miller AF-1 Air Flow Switch with Snap Acting SPDT Switch (Part Number 122800)

If the draft is verified with a manometer and the switch fails to close at -

Using a different horsepower or speed rating can disrupt the pressure switch calibration and lead to system lockout or heat exchanger damage

Designed as a direct coupled actuator (DCA)

Lochinvar & A.O. Smith 100074624 Valve 318973-401 Precise Calibration: Factory-set at -1For veteran contractors managing high efficiency hydronic systems, the Lochinvar & A. O. Smith 100074624 is a critical OEM component that serves dual functions as a flow adjustment valve and an integrated flow sensor. Engineered specifically for Lochinvar Knight and A. O. Smith tankless units, this valve provides the precise regulation necessary to maintain optimal delta T across the heat exchanger. By accurately monitoring and modulating fluid