McDonnell & Miller 150S-M-MD-HD

McDonnell & Miller 150S-M-MD-HD replaces 173302 with a robust 150 head, delivering precise boiler control through a reliable snap switch and a convenient manual reset. This high-quality head features a durable construction with corrosion-resistant components, designed to withstand vibration, temperature swings, and demanding industrial environments while maintaining accurate differential performance and long service life.

Ideal for commercial and industrial boilers, the 150S-M-MD-HD offers straightforward installation, consistent operation across a wide ambient range, and dependable safety interlock functionality. The unit provides stable cut-in and cut-out points under fluctuating loads and throttling conditions, with a mounting footprint that aligns with standard interface blocks. As a direct replacement part for 173302, it simplifies stocking, retrofits, and ongoing service, helping keep systems running smoothly and safely.

• 150 head with snap switch for durable, responsive operation
• Manual reset enables safe, quick re-engagement after trips
• Maximum differential provides reliable control across operating ranges
• Direct replacement for 173302 to simplify upgrades
• Compatible with standard boiler control systems for easy integration