McDonnell & Miller 354001 Switch 30067439-890 Technical accuracy is maintained via

Technical accuracy is maintained via a P399 electronic pressure transducer (sold separately)

and component replacements without losing the entire refrigerant charge

providing a versatile replacement for aging or failed 120V HSI controls

You must match the specific "Open" and "Close" settings to ensure the blower motor is moving sufficient air for safe combustion

preventing unsafe burner conditions and soot buildup

McDonnell & Miller 354001 Switch 30067439-890 Technical accuracy is maintained viaThe McDonnell & Miller 354001 is a professional grade E 11M 24V 2 SPST M R Switch engineered for critical low water cut off (LWCO) applications in residential and commercial boiler systems. This manual reset switch (M R) provides high reliability safety by latching open during a low water condition, requiring a technician to physically depress the reset button only after the proper water level has been restored. Built for durability in demanding