McDonnell & Miller 157S Controller R-410A Designed with a 1/2-inch crank

Designed with a 1/2-inch crank arm

21-27 bracket gasket

Proven Reliability: Features a liquid-filled sensing element for consistent accuracy across the aquastat controller lifecycle

This 120Vac valve typically features two lead wires for power and a ground wire

6 Amp draw remains within the unit's nameplate specifications

McDonnell & Miller 157S Controller R-410A Designed with a 1/2-inch crankThe McDonnell & Miller 157S is a heavy duty combination low water cut off and pump controller engineered for commercial and industrial steam and hot water boilers. This specific OEM part #173502 features the 157S series head mechanism (part #173003) equipped with a snap acting SPDT switch. Designed for high pressure applications up to 150 psi (10. 5 kg cm), this controller ensures precise liquid level management, acting as a critical failsafe by