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Critical HVAC ignition safety component that prevents hazardous unburned gas flow
making it suitable for both chilled water and hot water systems
Technical staff should note the specific 1/4" x 2-1/2" shaft dimensions
Union connections allow for easy removal and servicing without cutting the service lines
McDonnell & Miller 42S-HD Controller 30067439-890 Critical HVAC ignition safety componentThe McDonnell & Miller 42S HD Controller is a high performance head mechanism only designed for seamless integration into existing Series 42 S float chambers. This replacement head mechanism is engineered for technicians who need to restore steam boiler safety without the labor intensive process of breaking down equalizing piping. Featuring SPST snap action switches, this controller provides high reliability low water cut off protection and precise